It’s hard to do business online with people who have certain email addresses, due to the strict spam filtering used.
Yahoo, Hotmail, and AOL are some of the strictest. The main problem is that subscribers might not even see the email in some systems, making it critically important to avoid triggering the spam filter to start.
You’ll see all sorts of different techniques used to avoid triggering spam filters. One is to use punctuation inside of suspect words, such as using “fr*ee” instead of “free”. Personally, I think that gives emails an extremely unprofessional look. And, as a programmer, I could update a spam filter to find those punctuated words in about half an hour.
What I do is run my emails through a spam filter that tells me what it found before sending them out. Here’s the one I’ve used most recently.
What will happen is that you’ll copy the body of your email into the submission form on the page, and also fill in the from and the subject. When you click the button, it’ll run the email through a spam filter and give you the results. They say anything below a 4 or so is fine. With Hotmail getting ever more strict, I’d say to try and stick below 3 if possible.
If the word “free” comes up as a trigger, use some common phrases that mean the same thing, such as “no cost”. Try to avoid repeating the same word or phrase over and over, again substitute some of them with synonyms.
Cleaning up your emails before you send them will help to ensure they actually arrive.