This post started out as a reply to a Collin Hansen post on this subject. I found out about Collin's post by reading Justin Taylor's blog post. I located Taylor's post by using Google Reader, where I follow him, among others. (There, now I can't be accused of doing what I'm writing about!)
Some time ago, a few years after I wrote my doctoral dissertation, I was interested in trying to find out if anyone had used my work in any further work. I entered a few phrases in Google, and was surprised how many hits I got from people who had used my words, but clearly hadn't seen my dissertation. I know they hadn't seen it, because their work was published before mine was. I know I didn't use their work, because in the process of writing a dissertation, one becomes pretty familiar with the research he or she is consulting (for those who have written one, you will appreciate the humor of the understatement, I hope).
So, do this little experiment yourself-