For a good reason, here's some information and a warning: if you find comments in your blog right now with content like "I agree with you," you may be receiving a visit from a spammer. The spammers have figured out that in some blogs (especially newer WordPress versions) you need to have one approved comment before you can then use that address to post further comments—which of course are then just spam. So: even though it's nice when someone agrees with you, in this case you could be approving a Trojan horse comment.