There should be an easy way to tag a post, thread, or user, as spam, with a comment, to bring it to moderators' attention. As it is, there seems to be no way at all to do that other than finding a moderator to PM, which is inefficient.
At the very least... with zero extra development effort, we could maybe set up a thread where people can post to report spam posts/threads/users, that moderators should review regularly.
I nominate this thread.
And I start by pointing out this user: http://bitcointalk.org/index.php?action=profile;u=3108
he seems to have just registered and posted some inane posts, just to get some links in his sig pointing to some hyip stuff out there.