I got three comments on my web site from some guy who was trying to win some SEO challenge.  It dawned on me that he was actually trying to boost his web site by latching on to blogs and raising his page rank.  I felt a little stupid.  So now I am a little more weary about allowing others to post to my site.  I weed some of them out but its hard to know who’s who right?  It goes to show that if you are going to take the time to leave a comment, even if it is only a thank you, make it at least two sentences.  One for the thank you and the second for what you did with it.  At least you are passing on the value to others and making the post a little more legitimate.