If a large part of your email messages are not delivered, chances are they are mistakenly being deleted by anti-spam filters.
Here is a list of guidelines you should always follow when creating your email messages.
- If you’re using HTML emails, always include a text part in the email, for both recipients and anti-spam checkers, and the text should match as close as possible to the HTML copy. The closer they are in appearance, the less likely your email will be singled out as spam.
- Keep your message’s layout as simple as possible. Avoid complex formatting (Ok, it might look better, but less people will receive it).
- Pay particular attention to your mailing’s subject line: never use exclamation point (!), CAPITALIZATION, and words such as “free”, “guaranteed”, and text with spaces in between (t h i s i s g a p p y t e x t)
- Avoid generic salutation formulas such as “Dear User”; it is even better to avoid salutation all together.
- If you’re using HTML emails, use high quality HTML emails. Don’t use tools that generate horrendous HTML (example: MS Word). They often leave signs behind (like empty tags, eg: ) which are generally found in spam. Unbalanced tags and invalid tags will also flag an email as spam. If you use a title, make sure the title is meaningful — the default titles generated by HTML tools are often used as spamsign.
- Don’t insert active components (javascript, ActiveX, plug-ins) in your message. If you need rich media content, just link to a media-rich page on your web site.
- Don’t insert too many graphics in your message. The fewer images you use the more likely you’ll message will get through.
- Don’t link to IP addresses: avoid linking to IP addresses (like 192.168.xxx.xxx) in the message text, your e-mail will be marked as ‘scam’. Link to real domain names only (i.e. www.domain.ext).
- Avoid attaching files; use links to files hosted on a web server instead.
- Use email composition and mailing tools that work correctly. Well constructed emails (technically correct) can be readily identified as not-spam. Emails with missing MIME sections, invalid or missing message-ids, invalid or missing date headers, subject or other headers with unescaped unicode, etc., are likely signs of spam.
- Avoid useless or needless encodings. Don’t use base-64 encoded text unless you need to.
- Don’t include a disclaimer that your email isn’t spam. Don’t claim compliance with some legal criteria, especially one that is not actually law in your country. Only spam needs to claim compliance: non-spam is supposed to already be in compliance.
- Use normal conversational language; be sure not to use excessive spacing and or capitalization in your subject line.
- Do not use “cute” spellings, Don’t S.P.A.C.E out your words, don’t put str@nge |etters 0r characters in your emails.
- If you’re using HTML emails, do not use invisible web-bugs to track your emails. If you must track your emails to see whether they’re read, use visible graphics as part of your email, not invisible graphics.
- Don’t include gratuitous references to spam subjects. Don’t talk about Rolex watches, sexually oriented activities or drugs, or debt treatment, unless those topics directly relate to your email. And if they do, limit your email to one topic at a time. An email which mentions Rolex watches, Viagra, porn, and debt all in one email will very possibly trip over several rules that flag it as spam, even if everything else is clear.
- Don’t use tools used by spammers (i.e., advertised in spam).
- Use a well performing, well-administered and trusted SMTP server. Most undeliverable mails come from poor SMTP services, which often lead to being blacklisted: make sure your SMTP service’s staff is ready to help if you get blacklisted by mistake.
- Make sure your privacy policy, including enforcement, and including query contact information, is easily found and clearly stated on your web site. It’s good to include this information (where to find this policy, contact information), in your emails. Again, people who need to find out whether you’re a spammer will often look for that information: this will help you to stay out of blacklists.
- Be careful where you advertise, and be careful which advertisements you permit. If you advertise with companies that send out spam, your domains will be flagged as being related to spam. If you permit advertisements for those who spam, your domains will be flagged as being related to spam.
- Be careful which domains/companies you allow to advertise in your emails (if any). Allowing spammers to advertise will get your emails flagged by the URI blacklists. On the other hand, don’t advertise your domains with spammers — having your domain name listed in their spams can also get you flagged by some URI blacklists.