Hi all,
The WordPress community, by-and-large, has decided that Captchas are not a viable approach to stopping bots and other spam engines. They have gone with the
Akismet database approach, which seems to work very well on Links.com. Of course, with Akismet, there must be a way to moderate/delete/accept comments that Akismet has flagged. This might be a viable long term approach. Second to Akismet, a
Bad Behavior approach also seems to work well, though I think Akismet is the best first line defense, since Bad Behavior is known to lock out legitimate users (it once locked me out of my own site).
I am right now working out the plans for using Pligg for Links.com, and spam control is one of my top items on my list, since Links does get some heavy spam volume.
Rich