We know about the spam problems. The volume is partly due to the fact that the user database is shared with some of the other official WordPress sites. We don’t have a magic wand, however.
I get the same amount of spam on my site. I’m currently deleting one spammer every 10 minutes, and I am not sharing anything with official WordPress sites. Something is going on with Buddy/Word and someone needs to dig into it because this is insane. It isn’t just this site. It’s the code somewhere. I’m sure it’s WordPress because I have a wordpress only site running and the sign-up spam is ridiculous there too. I am not joking when I say every 10 minutes either. I’m freaking out.
You have our sympathies, spam is one of those issues that drives us all to distraction and not just from a WP/BP perspective.
There are some detailed thread on the support groups that list a great many steps that can be taken, please have a look through those and perhaps implement a few recommendations.
Closing this thread.