My first fear, once I realized that I had deleted some of the wrong accounts, was that I had accidentally deleted Matt or Mark's accounts. Fortunately, both of their accounts are still here. Unfortunately, a lot of regular members have been deleted (right now, I can see that Miss Foxy, County Mike, Primadawn, Silverback, Chris F, rearnakedchoke, and several others are gone).
I tried cleaning everything out in one mass delete, so that anyone with 0 posts, who hasn't even confirmed their email address yet, would have their account removed. Unfortunately, that just caused more database errors and internal server errors. So I'm having to go through and delete them month by month (based on the month that they joined). Just for example, there are over 5000 spam accounts in the database from the month of November 2011 alone.