As long as they only filter out the spam this is a good thing (though not even this should happen without the user's consent), but important mail or newsletters may fall victim to these spam filtering tactics, too. The ISP is certainly not doing this on purpose, so you should inform them about the situation to help avoid such false positives.
If you are suspecting that your ISP is filtering mail you do want to receive if you have signed up for an About newsletter, for example, but never got an issue, or delivery suddenly stopped:
- Visit your ISP's support Web site and look for their spam policy.
- Maybe you can opt out of the filtering,
- whitelist certain senders manually (to make sure you're receiving About newsletters, whitelist the "about.com" domain, for example) or
- report specific problems through a dedicated form.
- If you find neither of these options, contact your ISP via email or by phone and describe the problem with as much detail about the erroneously blocked email as possible.
In our example of About newsletters not showing up in your Inbox, tell your ISP something like:
I have recently signed up for a newsletter from About.com at <http://talk.about.com/>. I have yet to receive an installment.
Can this have something to do with server-side spam filters catching this wanted piece of mail? Could you please investigate this and maybe whitelist "about.com"?
thanks a lot!