I noticed that spam comments here have gotten a whole lot better. Before they were either blatant or of the "I love your site" stock comment. Now they are ad-lib and specific to the content of post, written like the person actually cares whats going on in the post. It's very subtle and there are no hyperlinks in the text, only the authors homepage links back.
I commend you spam people, you are really making an effort these days. I have fallen for it a few times too! And hey, maybe you guys really do own all those online casino's and porn sites that you include as your website.