During the whole Terri Schiavo saga, I started using what I called the "T score" for each FR thread, which was the number of posts before someone posted an off-topic reference to Terri Schiavo. I think the average "T score" was 7, and I actually saw a couple of "1" scores, where the original poster put in an off-topic comment in the initial post.
These days, it's morphed into an "I score", for illegal immigration. This thread has earned an "I score" of 4.
I like it!