Well, I too have been hit with comment spam. Comments such as "Hey great blog you have there. You might be interested in (insert worthless product here). Check it out!"
All bubbly and upbeat and blatant advertisements. I changed my blog so that only Blogger members could leave comments, but that didn't stop it; many had phony or not so phony accounts set up and who knows, maybe the spammers are using someone's legitimate account, much the same way they use valid email accounts to spread their garbage.
So I sent an email to Blogger complaining and copied the account info of some of the offending Blogger accounts. This morning I noticed that Blogger has a "Show word verification for comments" radio button now. I swear it wasn't there yesterday. I hate these things but I hate being the vehicle for these damn spammers even more. So now you'll get a gif with a warped set of letters to copy into a box before you can leave a comment. Sorry, I really am sorry; I didn't want to do this but "the spammers made me do it!" I realize this will probably cut down on the number of comments I get, but so be it. I am not going to spread the spammers word for them and also increase thier Google rank. Think of it, every page they get their damn link on will increase their rankings.