the SCAMMER tag is most appropriate for the forum.
the scammer db would probably arc across services, not be just for the forum.
on the other hand, google would probably find the bitcointalk forum entries quickly enough. even with scammers names, emails, etc. documented and pulling up #1 on google searches, people are still getting hit - obviously not even checking.
I like the idea of a scammer db, but share similar concerns about how information is vetted and moderated.
A tool has been created to help fill this niche in the #bitcoin-otc chatroom:
http://otc.armed.us/ It is not strictly devoted to scammers, but rather shows the pattern of events related to a name, hostmask, or other info. There are ways to add custom entries (like "SCAMMER" tag, "SQUATTER" tag, "SUSPECT" tag) as well.
http://otc.armed.us/the site could use a Help/FAQ. Search terms match an entire field, so use wildcard * around terms if you want to find any occurrence within a field, i.e.
http://otc.armed.us/?*rr.com*