On the advice of my brother, I’m trying out a centralized spam filtering service called OnlyMyEmail.com. Already in less than 10 hours, it’s caught over 600 spam messages that normally I would have had to process on my own CPU at great processing and disk space expense. As far as I can tell it’s had only one false-positive, and missed two spams. Not bad!
If the service proves to be reliable, I’m going to stick with it, and quite happily pay the $3.00/month to not have to spend hours every week deleting missed spam manually.
OnlyMyEmail.com does something pretty simple on the face of it. You configure their server to check up to two POP or IMAP email accounts, which it seems to do about every 5 or 10 minutes. They filter all the spam, and delete the messages from the primary server, and store the real mail, which your POP client then reads. If you want, you can review the spam messages for up to a week, and mark them as not spam. They also have web-based mail, though most likely not as nice as Yahoo Mail or gmail.
Like other similar services, you can maintain both white- and black-lists for email addresses which are always blocked or always allowed. You also have some rather high-level preferences for what kind of mail to block and what kind to let through.
What seems to be unique about OnlyMyEmail.com, at least according to their description, is that they use multiple spam filter algorithms, which all seem to be fairly aggressive. But instead of running the filters together in series, they do a logical OR operation on the filter results, so that a message which isn’t marked as spam by all filters gets through. This means you’re a lot less likely to get false positives and miss mail. From the results I’ve seen so far, this seems to be a very successful strategy.
They have a service that runs on a whole mail server too. It acts as an SMTP proxy via the MX record in your DNS tables. I’m not sure what that costs though — I bet it’s a lot more than $3.00/month. This is where the real money is in third-party spam filters, if you asked me.
I wonder if something like this could work for the weblog world, for dealing with comment/TrackBack spam and spamblogs that aim to game the search engines. Haven’t put much thought into it, but maybe there’s something there.