I just installed Akismet – the “official” antispam solution for WordPress. Ok. It’s not really official, but it’s written by PhotoMatt – the lead of WordPress – which makes it official enough.
I’m a bit nervous about deactivating Spam Karma 2 – which has performed absolutely flawlessly (and silently), but am curious about the distributed spamblocking approach used by Akismet, as opposed to a personal blacklist used by SK2.
And, if Akismet fails miserably, it’s just a matter of clicking two links in the Plugin Manager to go back to SK2. One caveat to Akismet: you need a WordPress.com API key to activate it. Download a copy of Flock to get one if you don’t have one already.