Spam is unsolicited bulk email, or junk mail. Spam filters are programs that look for certain words or phrases in an email's subject line or body (known as trigger words) that suggest that an email is Spam. Spam filters work by analysing the email, and giving each word or phrase a score. The total email score is then calculating and if the total is more than the Spam filter will accept, your email will be classified as Spam and sent to the Spam bin or even prevented from reaching the recipient’s computer.
To Keep your Emails out of the Spam bin:
Check your Spam score - when you are editing your Email Campaign, always ensure you check your Spam score. The higher the score, the more likely your email will be to end up in the Spam bin. If your score is 5, your email will not send. See the help article Understanding your Spam Score for more information.
Avoid using risky words or phrases - these include Free!, Click Here, You’re a Winner!, Information you requested, Amazing, Loans, Credit, Viagra, and You’ve Been Selected.
Using all capitals - this is the text equivalent of shouting, and will easily trigger spam filters. Capitals should only be used for the whole word if it’s an acronym, so be sparing in it’s use.
Symbols - Frequently using quotation marks, dollar signs and exclamation points will also trigger the spam filter. Use them only where it’s appropriate to do so.
Check your subject line - every spam filter pays particular attention to the subject line, so make sure it doesn’t contain any risky words or phrases.
Use Text Only Emails - Most of the time, you’ll want to send a HTML email, so you can add images and links to your email. However, spam filters prefer Text Only emails, so if you want to send HTML emails, always ensure you send a Text Only with it.
Avoid all image emails - spam filters judge the ratio of image content to text content in your emails. If your email is image heavy, it’s more likely to be flagged as spam. Another side effect of images is that firewalls will often remove images from an email to prevent virus or spyware infection, which means your email will end up looking like a blank page with just a tiny bit of text. Always make sure the majority of your email is text, with just a few images to support it.