To prevent spam that is posted by computer programs, Blogger has come up with a word verification system.
Now, when you post a comment, you'll see an image of word, such as the one to the right. You'll need to enter those letters into the appropriate box or you won't be able to post your comment.
As always, you will still be allowed to post anonymously or without even having to sign up for a Blogger account. If this system works in cutting down the spam, we won't have to consider going any further. Keep your fingers crossed!