Clients often ask me how we make sure we avoid the spam folders. Spam filters are looking for signals and flags to determine if a message is spam or not.
There are essentially 2 types of flags for spam filters:
Making sure both the sending service (ie MailChimp), and the sending domain (your website) have good sender reputation, that is, the email from the servers don’t get flagged by users very often. Each receiving server (ie, Hotmail, Gmail, Outlook) keeps records of the reputation of past campaigns for each sender, and it develops a trust profile. If you’re using Campaign Monitor, receiving servers will have a profile of both Campaign Monitor, and your own domain. If you’re using a reputable sending service like Campaign Monitor or MailChimp, you’re halfway there and now you need to make sure your domain doesn’t send any content that might get marked as spam. If you try sending a big blast from your own server or a cheap alternative, the receivers will be suspicious of a large volume of emails from a unknown server.
This is everything from the subject line through to content and HTML coding. It’s mostly common sense – don’t use ALL CAPS in the subject line and use “free”, “$”, “% off”, and “bonus” all sparingly. There are other indications of spam content, such as emails with all images and no text, bad grammar, weirdly coded emails and no alt text in images, but the big factors are the spam words above.
In the same vein as the Reputation, if users repeatedly manually report you as spam, you can dramatically increase your spam profile with receiving servers. This will increase the liklihood that your emails will end up in spam filters of other users in the future. The main reason for being manually reported is because users either didn’t sign up for your messages, or don’t remember signing up. Make sure you have correct permission to send to your users, and when you do, communicate with them regularly so they don’t forget signing up. If you are concerned about being marked as spam, make it easy to unsubscribe so they hit unsubscribe instead of reporting you as spam. As much as it hurts to lose a subscriber and the perceived potential sales, it will hurt even more in the long run if you have bad sender reputation and don’t land in the inboxes of those who choose to stay.