Akismet is a great product and service. The benefits far outweigh the drawbacks. That being said, I’ve had some interesting false positives (FPs) this week. A couple of comments from someone who’s previously submitted approved comments were tagged by Akismet. I guess that’s going to happen but what really surprised me was when a registered user (contributer) commented, it was tagged as spam by Akismet.
As I’ve mentioned previously, Bad Behavior and Project Honeypot greatly reduce the load that Akismet deals with on my blog so it’s not a killer to review the Akismet spam queue. There’s usually only 1 or 2 spam in there but it seems to me that registered users should be exempt from Akismet screening.