My personal opinion is that a thread can have a lot of lurkers during the first 50 posts. Some may plow through the first 100, but not that many. That's why I usually don't deploy the ping list if I learn of a thread after it's past that point. After 100 posts, it's just too late to argue with a creationist, or even to post a link with the correct information. The lurkers aren't there to benefit, and for sure the creationist won't benefit. But sometimes I do it.
Well, you do know that I am mainly a lurker on these Evo/Creo/ID threads...and I read each and every post, no matter how long the thread goes on...I would have to imagine, that if I take the time to read everything, that other lurkers do as well...
For what it is worth, we lurkers do appreciate the posts from everyone, regardless of their position on this subject...