This, from a commenter at Slashdot’s AOL Won’t Budge on Email Tax:
If an AOL user has you in their whitelist, you bypass all spam filters. No fees, no forms to fill out, no feedback loop to maintain, nothing. So all these charities just need to tell their users to put them in their whitelist before signing up for mailing lists or whatever. Lots of sites do this already, because they are aware of spam filters.
Haven’t found this tidbit in any of the flaming rhetoric floating around to date (and I frankly can’t verify AOL functionality because I am not with them), but it has been discussed before – personal whitelists.