[edgeztv]

An easy way for Google to fix the problem:

Lemma: most users are subscribed to Google Groups with their Gmail addresses.

Algorithm: GG should broadcast a new message to the Gmail accounts first and wait. If Gmail flags it as spam for p% of the receiving accounts, it should notify GG. GG should then send the message to spam (e.g. hold it for moderation), and not broadcast it to the rest of the subscribers. If Gmail gives it a green light, let it through.

[bartl]

Google Groups is basically just a window to newsgroups (AKA usenet). You can post to usenet directly, bypassing Google' posting police.

[mkelly]

Or hook Groups up directly to whatever spam filtering mechanism Gmail already uses. No idea if the architecture makes that easy or not.