Humanist spam...

Today I got dead-tree spam from the British Humanist Association. I'm wondering if this was a side-effect of donating to the Atheist Bus thing - if so, surely that's going to wind people up? If not, I can't figure out where else they'd have happened upon me (I'm assuming it's targeted, given my general sympathy to their cause).

Did anyone else who donated to the bus get a 'join us now' pack in the post?