A person signed up to "follow" me at Twitter, someone I didn't know. I checked out her Twitter. She hasn't posted in several weeks, the posts she has don't really make sense, and she's following forty-six thousand people!
I suspect this is some kind of Twitter spambot. So I blocked her.
Is that cool?
[EDIT] In the past five minutes I've just been added by another Twitterer who is following several thousand people, and who has only posted one message, packed with mis-spellings and an invite to follow a link.
Now I understand the idea behind Twitter. It's like a hunting preserve for spammers! Do you suppose the Twitter founders make a few cents for every spammer that is reciprocally followed? Otherwise, what's their business model? Maybe to create a huge social network like MySpace or Facebook and then sell it for ten-billion dollars?
Anyway, I've answered my own question: block 'em!