Spam filters?

[ciphergoth]

What's the best way to check what might be causing my mail to end up in spam filters? According to this search I'm not blacklisted:

http://www.mxtoolbox.com/SuperTool.aspx?action=blacklist%3a80.68.89.15

but I've been finding it pretty difficult to reach people lately, and starting to think some sort of spam filtering might be responsible. Any ideas?

Comments

[babysimon]

We've tested it against SpamHaus and (non-Bayes) SpamAssassin here and doesn't seem to be either of those.