When sending email it can prove difficult to get in the inbox but ensuring that your email campaign does get delivered is of course the idea. But due to spammers, lots and lots of technology sand time has been invested to intercept spam and redirect it to the junk folder so that only the email you want is in your inbox.
The ways of filtering emails are content and reputation.
The most common cause of junking in legitimate marketing emails is content. Content filters were created to help stop proper spam, like viagra, replica watches and African money scams flooding peoples’ inboxes and getting in the way of email that recipients actually want and asked for. Of course it is impossible to rid the inbox of all junk without catching the occasional good email, which is why there is a junk folder for people to occasionally check if they are missing an email they expected.
The key to ensuring content filters don’t confuse your email with spam is to avoid your email looking like spam, unfortunately not all of the things you need to do are obvious.
Points to consider are:
- If you are sending HTML content, ensure you also have a plain text version
- Don’t make your subject line all capitals
- Make sure your ‘from name’ (sometimes called ‘friendly from’) is an actual word(s) and not a URL – i.e.: don’t put .com en the end of it
- Ensure your HMTL content has at least 3 images and not all of them touching
- Ensure your HTML content has at least 60% text and at most 40% images
After that any problems will be smaller irregular things like spammy keyword combinations.
All of these things will be noticed by a spam or deliverabilty checker and any decent ESP will have one. Also services like Litmus, Return Path and Email on Acid offer them as a separate service along with inbox preview tools which will give you previews of how your HTML will be displayed in different inboxes. Some ESPs have this feature integrated into their software.
Over the years it has become evident that most spam is sent by virally infected computers, which scrape the web and send spam out from that box. ISPs have realised that if they just blocklist that box and ignore any emails from it, they save a lot of time and processing power because they do not have to scan the content to make a decision.
As email has progressed ISPs have found there is a big grey area between wanted email and actual spam – this would be the emails sent by actual people and business that recipients don’t want – recipients also call this spam. In order to help decide how to treat emails, ISPs have developed a reputation based system to sit in between blocked and unblocked. This reputation then decides how many emails you can send to ISPs in a short space of time before they start to soft-bounce (defer) them to be sent again later. This is because spam-bots do not respond to this, so only real emails got resent.
Most of the big consumer ISPs use every metric they can from your emails to measure and identify you, this includes:
- The IP address of the system that sent it
- The domain in the from email address
- The whole email address
- The word to the left of the @ sign
The reputations assigned to these things per sender are then decided on by the recipients’ reaction to the emails they receive.
The below are all positive actions which will improve and maintain the reputation of a sender meaning that their inbox placement will be better:
- Opens over time
- Click through rates
- Adding the from address to the address book and/or safelist
- Requesting to always load the images
- Marking as not spam
- Hitting a spam trap
The bullets below will all negatively affect reputation and make it harder to get high volumes into the inbox:
- Marking as spam
- Hard bounces
- Consistent soft bounces
- Ignoring emails
- Spam traps
This is one of many Best Practice Guides I have written for Pure360, they are all archived on this site in one form or another., If you’d like to see the full polished version search for best practice on Pure360.co.uk.