Well, it doesn't eliminate ANY of my legitimate email; have you actually tried it? The reason probably is that anytime I respond to someone, I automatically have their email address added to outlook. When you install Choicemail it imports ALL of those email addresses and puts them to the "white list"; anyone not on the whitelist gets sent an email asking for authorization;

Thats great if you never expect much mail beyond a few friends. But, if someone comes across your site and has an interest in mailing you, that interest may not follow long enough to wait for a reply that states they need to be registered to e-mail you. Also, I would never use such a service for the e-mail address that sits on my resume. I'd personally never hire someone not interested in hearing my response without making me hop through hoops.

Think of it this way. I am the one behind the [email protected] address. (The address that is e-mailed when you use the "Email BBS Admin" at the bottom). Would you appreciate it if you had sent me an urgent request for help, to only see a reply siting in your inbox hours later (thanks to some e-mail delay somewhere) asking you to register before the e-mail will be accepted again?

I believe in two things with spam:
1. Never delete a single thing. Flag it and toss it into a folder to be reviewed every once in a while. If I hadn't done this, I would have tossed a few critical things that managed to get tagged as spam.
2. Never make the sender change their normal patterns. The system some ISPs use is a database that is built by generating an automatic reply and seeing if it bounces. This still can cause problems if it's deleting mail, but works great as an additional flag.