ISPs reveal deliverability tips for their own inboxes

Deliverability Facts from the horses mouth

This year’s Email Evolution conference from the EEC had a very popular and enlightening last talk; representatives from Gmail,, Aol and Comcast revealed some great details about how their platforms handle reputation and inbox placement.

Spam Traps

I have mentioned before about Yahoo, Hotmail and AOL recycling dead addresses into traps, I didn’t invent the idea it was from research and close sources. have now denied it and AOL said it had happened but not if it still was. also stated that an account would be shut-down after 2 years of inactivity, not the 7-14 months we had previously been led to believe.

Gmail confirmed that there was no recycling but they have not been around for long compared to the rest so have no need for it … yet.


  • Opens – Good, obvious engagement
  • Clicks – no-one tracks clicks, it’s a breach in privacy.
  • Replies – Good, signifies a conversation
  • Mark as Spam – Bad, of course
  • Mark as Not Spam – Good, big noise that the ISP has got it wrong
  • Delete without Opening – Bad, signals no interest but with less offense than a mark as spam
  • Move to a folder – Good, signals value in the email’s content
  • Add to address book – Good, signals value in the sender.

The only new one on me here was adding to a folder but it makes sense, it’s a keeper.

No mention of stars (or pins) though, I’d expected that to be good one. Unless it’s such a short term thing it carries little weight whereas folders (labels) are more permanent.

Inactives said that inactive subscribers do not affect/increase reputation based junking but in an individual’s inbox it may. Subsequently they do not support the notion that kulling the list of inactives will help reputation but added that the people who rarely open your emails are more likely are to take negative actions.

Gmail didn’t openly agree with and they suggest going with a ramp-down for frequency of emails to inactives before you stop sending to them at

Daily ramps down to weekly, weekly ramps down to bi-monthly or just monthly etc. etc.

I was a little surprise that they suggest stopping all together from 3-6 months, however, this may have been more targeted to daily senders but apparently the Gmail marketing teams are advised to abide by this.

I’ve always been of the opinion that there was a level of percentages being applied to volumes sent that would affect reputation, rather than just reducing actual actions that were negative. Senders who have had higher open rates have always enjoyed more content freedom and sending volumes & speeds. This may not be the case in and they may put more weight on actual reactions.

The ramp-down has legs though. We already have a ramp up for new IPs.

If you do a ramp down, don’t just keep the same content, pick and choose and experiment, you need to get an open from these people so they get back in the engaged segment … more to come on that I expect.


The short version is that not being authenticated is just bad!

DKIM plays a big part in most inboxes nowadays but it is rumoured that SPF makes little difference even to who championed/invented SenderID as the evolution of it but it’s best to have at least those two at all times. DMARC is newer and not yet a requirement, most ISPs use it themselves but do not make it a requirement for delivery.

Content Filters

All agreed that there were no longer any “spammy keywords” which their systems looked for to decide on inbox placement. However, certain copy in the subject and content are more likely to result in negative reactions from users and reputation could then be affected.

I personally have found that I can take out certain collections of words on a junked email and get inboxed in and Gmail.

I’m of the belief that either those content filters do exist and the leniency of their filters depend on reputation.

Alternatively actual copy can have reputation, whether it is a word or a collection of words, which could be learned from user actions. This could have been an evolution of the old bayesian filters.

Either way they so it ain’t so.


Deliverability is personal to each inbox

… was the catchphrase, which essentially concurs with any deliverabiltiy experts’ advice:

reputation is one thing but each person uses their inbox differently and gets different emails, so each inbox learns differently so can react differently.

So it’s nice to get something from the horses mouth. From experience, I’m not ready to accept all of it at face value but I will adapt my priorities slightly. I hope this is of use to anyone else.



Further Reading

AOL, Comcast, Gmail, and open up at EEC15” by Massimo Arrigoni
How 4 Of The Top Mailbox Providers (Isp) Determine What Gets To The Inbox” by Al Bsharah

Image from

Mark multiple emails as not Spam in Gmail


How to mark multiple emails from the same sender as Not Spam in Gmail desktop


As you may know, marking as not junk is a good for reputation.
One mark as not spam counts for more than one mark as spam.
This is because you are telling the Inbox provider that they have got it wrong and you nearly missed an email which you wanted.

It is easy to mark one email as not junk, go to your spam folder open it and click the “not spam” button. Alternatively you tick the email or all the emails in the spam folder you want and choose “not spam” in the control at the top.
If you want to mark all the emails from one sender as not junk, they are unlikely to all be on the same screen to tick them all, so you do a search.
If you select all emails from your search you don’t get the option to mark them as “not spam”.
This is because you are in the search screen and not the junk folder.

To be able to mark them all as “not spam” follow the process to search for all the emails in your junk from one one sender. You then click the tick box at the top to tick them all. Then click the “spam” folder label to take you back to the spam folder.
Once in the junk folder, you will find that all the emails you had previously ticked are still ticked.
Now you have a “not spam” button; if you click it you will have mass marked all emails from one sender as not spam.

If you want to go a step further and mark all the unread ones as read, you should do this by opening each one. This is because marking as read without opening is also not good for your deliverabiltiy reputation.

An easy way to do this is to search to find all emails from that sender which are unread,
eg: “is:unread from:dave@daves.dave”.

Then click to open the oldest one.
Once in the oldest email you will see left and right arrow buttons in the top right. Use the left arrow button to take you through each email one at a time from oldest to newest. this will open each one individually and save any damage to reputation.

[image from Spam Nightlight on Etsy – there are a few other novel spam items there too]

Querying your responsive terminology


Querying your responsive terminology

There’s a fair few phrases banging about regarding responsive emails and the term “responsive” itself is one of the most argued terms.

Having HTML render differently on a smaller screen was of course led by web-pages and emails caught up as much as they could, battling through the endless quirks of the many inboxes which an email can be smashed to bits by.

What seems to be the core of the terminology of site design structure is four terms:
Fixed, Fluid, Adaptive, and Responsive.

Fixed – all elements’ widths are set and stay that way on any device

Fluid – all elements’ widths are percentages and the elements will grow and shrink to fit the browser window/device screen.

Adaptive – all elements widths are set to fit the average screen size – media queries are then written to force elements to change at set max and or min screen width sizes. This can be any attribute which CSS can alter, from widths to display, to positioning and more.

Responsive – this where websites are built in a fluid fashion but also use media queries to alter the structure to suit different screens.

But when it gets to email, the jargon seems to get very muddy because you don’t have the luxury off all CSS in all inboxes and you have to use tables to hold them together.

A fully fluid approach is a bit restrictive because you are tied down to a single column that grows with the screen. Nice enough of course, looks great on a mobile but does not make the best use of the space available on desktop and browser inboxes. You don’t have any media queries and it can be a bit of mess with so many screen sizes on desktops too and is subsequently rarely attempted.

An adaptive approach is very popular because most smart phones have a similar screen size so you just set the breakpoint for the largest phone eg: 320px and bring your desktop optimised fixed width multi-column email down into one column and have new fixed widths.
The downside of this is that the reliance on media queries means that it only really works on an iPhone; Android email clients’ support of the media query is poor – although Google have dropped hints that they want to get them working on their Gmail apps now they have dropped Android’s native email from future Android versions.

The other slight downside is having the set width for one phone screen could mean the email does not make best of use of larger phone screens in order to work on the smaller.
So the most popular method is to build for the desktop with mainly fixed widths but with some fluid to help for larger mobile screens and the then use a media query to change the structure down to one column and then use percentage widths so they make the most use of each screen size.

This method tends to be called “responsive”. This makes sense to me as it is a mixture of adaptive and fluid.
But there has been some disagreement over that being truly “responsive”.

The phrase “responsive email” is also used as an umbrella term for any email or web-page which alters in any way to optimise itself for more than one screen size.

It has also been argued (badly) that the use of percentages on the phone’s media query making each block’s width 100% on a phone does not count as fluid because it comes after an adaptive screens size cut off …. this holds very little weight in my mind.

This discussion got a little heated on Twitter recently when someone was not happy that the social icons on a certain newsletter were apparently too big when it adapted for the iPhone and they went further to state it wasn’t responsive it was adaptive.

From my point of view any email which alters its structure for different screen sizes can call itself “responsive”, whether it is purely adaptive or uses fluidity as well or alone where possible.
The method(s) you use for this responsiveness would then become the more granular description of how you made it responsive.

For an email not be responsive it would have to 100% fixed width and not make any allowances to be altered from its original desktop version on the phone or vice versa if is a fixed width slim email built for a slim screen over a wider desktop.
On that note, if you ever feel you have the decide between fixed width slim and fixed width desktop, choose desktop. Everyone knows how to pinch zoom on a mobile but not as many people as you’d think know how to zoom in on a desktop. But pay attention to the clicks by device. it is likely that mobiles will get more opens than a desktop but rarely as many clicks due to the inbox triage. If you are getting good traffic from smartphones, then pay more attention to them.

To add to all of this, it was all changed again during completely email in London last week when Mike Ragan of industry leading email development firm Action Rocket wrote off Fluid as a viable label for email and introduced their new term “Hybrid”, I’m sure I’ll discuss this in another post.

Subject line personalisation


Is Rumpelstiltskin on your list?

Personalisation in the subject line is great thing, making an email more personal can only be a good thing, unless you go too far and get a bit stalky if you get too familiar.
The effectiveness of subject line personalisation is a combination of how you use it and the rapport of each recipient.

Back in the old days of B2B acquisition emailing where postal marketers applied the same method to email, ie: buy a list; they would use personalisation in the subject line to try and fool the recipient into thinking they had a prior relationship with the sender that they had forgotten about.

You see it in real spam every day, where they take the prefix from your email address to try to get you to open it. It’s a numbers game, sometimes the prefix might actually make sense but rarely.

Nowadays people are wiser because it’s been done to death and everyone knows, it’s also hard to make a subject line make sense with personalisation.
Subsequently unless the rapport is great, personalised subject lines are likely to be treated with suspicion.

The subject line is a title, a teaser, the start of a story, a brief contents list if you’re out of ideas adding my name to it will be hard to have it make sense, eg:

“Todays top deals for you Andy” or “Andy, here are the 3 best things to happen this week”
or even worse “3 super cheap holidays for Andy” – not even addressing me.

It’s like a brand is shouting “I KNOW YOUR NAME, YOU MUST NOW OPEN MY EMAIL!”.
That’s not going to work, unless of course I’m Rumpelstiltskin at which point I will of course be compelled to do so.

There are a few of angles which can help though:

Only do this if the data is right.

If there is a chance that you don’t have the right first name, don’t chance it.
Either get the segment perfect or do some build up and ask the question, link to a form and then personalise the people who update their profiles.

If you personalise the subject, personalise the whole email.
Just adding a first name to a subject and nothing else will be an obvious gimmick and will not be popular, unless it’s really really funny. If you can make the whole email personalised or at least seem it, the recipient will get that personal touch from you. This is more than just putting in the first name where you can and you need to use data about them which you have earned not bought otherwise they’ll hate you.

Don’t do it every time

you can do it every time if you like but the pattern will get dry and you’ll just be wasting inbox space. Your from name is where the rapport starts and the subject is the priority.
Adding personalisation every so often, for a special email, will get that boost.
This can be a handy tool for early re-engagement, people who haven’t opened for 3-6 months, for instance.

Get it in the inbox snippet preview

This is a cheeky little trick. As you know, most inboxes will take the top line or two (or three – iPhone6+) of your email’s copy and stick it after the subject line. The idea was to give users that extra bit of information to help them decide and help avoid the odd click-bait subject line. Of course lazy marketers haven’t noticed this and still insist on having “can’t this email…” blurb at the top so that’s what ends up in the inbox, doh!
The idea is to make that very top line in the very top left of the content elaborate and compliment the subject line.
This is a great spot for a first name. In the inbox, after the bold subject line, in lighter text will be your name and the start of the story cut off by the inbox where you will then be compelled to open the email to see the rest of the sentence that your name was in. Alright that might be a little exaggerated but the point is clear.

Here’s a little example from Gmail’s desktop webapp:



Why not give it a go or even do it on a content A/B test.



image created from screenshot of “Once Upon a Time” TV show and a photo of an iPhone 6+

Watch out for plain text


Watch out for plain text

As you ‘should’ know, a plain text version of your email is vital for inbox access; Viruses and spammers often don’t bother so content filters lookout for it.

Way back in the days before the WWW, email existed. You sent plain text messages between computers/terminals and the file was a header and the content  – plain text. Then later on, the web was made and HTML was bolted onto the bottom of the mime and email marketing grew.

Over time more and more inboxes would render the HTML and now, pretty much all of them do by default – even blackberrys!

So you just made it quickly with the click of a button or it is made for you and you haven’t had to care about it for quite a while, But now you do!

Phones are getting bigger and to fill the void of the tiny smart gadget, wearables are appearing – most notably the Watch!

Word on the web is that it is very likely that Apple’s smart watch: “Apple Watch” will render full emails but only the plain text version and due to the novelty of it, they are likely to read it or at least the start, they could continue to read the plain text or handoff to the phone.

Either way, your plain text will likely start to matter but you likely won’t know about it because there’s no open tracking in plain text, only link tracking and the likelihood of clicks on a watch is slimmer than a phone, however there is a chance they’ll handoff the click down to the phone – if that’s an option – it should be!

In fact they should let you queue up the pages you click to so you triage the inbox then get your phone out and the pages are loaded and ready!

Make sure you check the plain text version of your emails is structured in an accessible way, especially the top 3rd.

Fun with Background Images


This week I’ve mostly been trying to get one dark background image to render behind the message copy, which is white; on Outlook and the big three consumer ISPs: Gmail, Hotmail, Yahoo.

Those of you who know, know…

Each inbox has it’s own preferences about what it will render and how it wants you to code it; background images are one of the more complex. Here’s why:

body color body image table color table image
Outlook Y Y Y N (vml*)
Gmail Y (inline**) Y (inline**) Y Y
Hotmail N N Y Y
Yahoo N N Y Y


*Outlook does not support background images on tables or tds, however there is a workaround using VML, this technique is known as “bullet proof backgrounds”.
**Gmail will obey styling of the body tag but the code must be added to the body tag directly because it converts body tags into a div tag but will leave the rest of the contents of the tag in place.

You might ask why there are no mobile clients in there, it’s because if I get these right, the others will work too … or will they? answers on a postcard.
Note: Call the background color before the image in all tags, otherwise the color will be rendered last which will put it on top of the image and you won’t see the image.


Essentially Outlook wants the image and fall back color added to the body, style tag will work. Gmail needs it inline to the body or on a 100% wrapping table. Yahoo and Hotmail won’t render body styling so you have to add it to the wrapper table.

The complication is that while Outlook won’t render the table image it will render the table background color, so where you have added a background color to the table for when Yahoo and Hotmail block the images, Outlook will not show that image at all but will show the colour and that will be in front of the image on the body.

If I leave the color out of the table Yahoo and Hotmail will look terrible because the copy is white so won’t be readable on the white background.

What do you do?

One answer is to use a bullet proof background, this is Outlook specific code called VML to make Outlook render the image. There is a free little tool to automatically make the code on Campaign Monitor’s site.

This would work in most scenarios, however on this occasion, my customer had an antiquated system which cannot handle the VML code. On top of that I prefer to only go down this route as a last resort.

Instead I just used the [if mso] trick!

Initially I had to code in the background colour and images in the following places:

  • To the body tag in CSS in a style tag inside the body tag
  • To the id of the wrapper table in the style tag
  • Inline on the bodytag as an html attribute and in CSS
  • Inline on the wrapping table as an html attribute and in CSS

This will work everywhere except Outlook where the table background colour will show in front of the body background image.

Then I simply add an [if mso] comment block underneath the style tag. This block will include another style tag which also refers to the wrapping table and makes the background color transparent, ie:

<!--[if mso]>
<style type="text/css">
#backgroundTable {background-color:transparent !important;}

This essentially turns off the background coloring on the wrapping table but only in Outlook and all is well in the world.

One thing I have not spent the time to test is the number of times I’ve coded the background image. I’m fairly sure that using html attributes and using inline css is a bit overkill, however I’m not sure if one engine prefers inline and another prefers html or either either will work and I just need to pick one. Hopefully inline css is the winner; if you know, let me know!

If only there was an easier way – if you know, let me know…