Jon Udell wrote about whitelisting and ChoiceMail earlier this month, and rightly pointed out that such mechanisms were in some ways evidence that in trying to combat UCE we were losing the general efficacy of email.
I just read (via Der Schockwellenreiter) about another potential assault (albeit seemingly well-meant) on the same. Wired reports on a charging plan for spammers, with mechanisms that would allow genuine emails to get through.
I don’t know what the answer is. For now, I’m happy, having installed the excellent SpamAssassin and enjoying virtually spam-free email bliss.