Whitelisting, as you describe, is very effective. As with any SPAM solution, however, it's not perfect. There may be times an unknown sender sends you something that you actually want to read. This potential situation can be mitigated somewhat by a challenge/response technique, such as the whitelisting tool Qurb offers: http://qurb.com/.

On another front, Bayesian filters are deadly accurate in detecting spam. Bayesian filters fatally attack spammers' Achilles Heel -- the message that they have to get through in order to do their dirty work.

Incoming messages are parsed, and the words are stored in a database. As you approve and reject messages, a statistic is developed based on probability and percentages -- the filter gets smarter as you use it. It learns what you consider to be SPAM.

You can find an excellent free Bayesian filter tool called POPFile at http://popfile.sourceforge.net/. It works as a proxy between your mail client and server, and its management interface is browser-based. It's written in Perl; you can put a shortcut in your Startup folder, or you can run it as a service.

I get on the order of 100-150 SPAMs a day, and my filter is up to 98.26% accuracy. I don't know how I ever lived without it.

HTH



>Hi Colin
>I consider any email SPAM that is unsolicited coming from anyone I don't know, no matter what the subject may be. I think that the ultimate spam filter would probably be the easiest to implement. I maintain an address book that contains the email addresses of those that I correspond with as I'm sure everyone does. Why not use this address book to filter the email and only allow mail from someone in your address book to be delivered to your inbox. All others could be routed to a folder as "suspected junk mail" that you could peruse and add addresses to your address book if desired to prevent future filtering. This junk folder could be automatically purged after x number of days to prevent it from becoming unmanageable.
>
>I believe that this would be the simplest, most effective filter that could be devised.
>
>Key word filters are difficult to maintain and many times filter out real mail. Maintaining a list of addresses that you won't accept (blacklisted addresses) simply does not work since there is almost an infinite number of addresses that send out spam and spammers simply change addresses, cloak their address, or hijack legimatate addresses and continue to sent their crap.