If spammers go to all the trouble of inundating us with their "check out my website at ...." messages, why don't they take the time to write (or to program their computer to write) a coherent message, or at least one appropriate to the post they attach the comment to?
A typical sample:
Hey There, I found your blog the usage of msn. That is a really well written article, I'll be sure to book mark it and return to read extra of your helpful info. Thanks for the post. I'll definitely return. Also visit my page - http://etc.etc.etc.
My really well written article referred to in the spam was the YouTube video of the Rocky Fellers singing Killer Joe.