Looking at the whole decline of BCSB thread and spam, few ideas that may be worth looking into (some may disagree but whatever )
Idea for new sub forum: Called "Introduce yourself" or something like that. Once new user signs up, he is automatically taken there, and this is the only place they can post for 1st 5 or whatever messages. Forces new people to introduce themselves. This place should be free of any crap, bashing and such. Kinda like safe zone if you will. While there is a new rider forum which is similar to this, introduction one will be non bike question specific and just used to make new peeps welcomed. This place should be 0 tolerance for any bashing, no matter how stupid question or person may look.
In here there should be some sort of a sticky. Talk about whatever, search function, rules, hints and tips on how not to piss people off (which is a biggie around here), more info on some of the sub forums and so on.
Also this way all of the potential bots are stuck in here and instead of modding 10 sub forums, there is only one to monitor.
I have seen several large sites do this and it works out really well.
And as few have mentioned in decline thread, perhaps some of the sub forums should be killed, merged or whatever. No point in some of them as they get used only once in a month, if that.