I spent about an hour on all my blogs -- several that I use for different purposes -- deleting all the comments, except for REAL comments. Most of them were Chinese, which I cannot understand, and had links to adult sites that I'm not interested in.
I'm not against Chinese, per se, but it really is a pain to rid all those dumb links. So now I require a word-test before each blog comment. I don't mind REAL comments, even if they are negative. I just don't like SPAM.