I'd bet about 75% of the people read no more than the title and then skip to the bottom and start posting. About 20% read the first post in the thread and the remaining 5% well I'm not niave to say they read all the posts.

Too many times you find a wealth of information hidden in a post you would have thought was a dud.

I've keep my mouth shut for some time trying to see traffic direction of my sites. it's safe to say that this quote is so true. I've pushed some of my traffic (nothing fancy) and I've got nice return from blog directories. So right now I'm on 300-400 hits daily from them witch is nice :D
and I'm seeing bookmarkers increase. I'd like to believe it's because every now and then I do make a post worth reading ;-)
now, about that reading thingy ... I have to say my surfers tend not to do it in those average 10seconds they stay on my site |huh

To me, and I could be wrong, one thing seems to work good is a character or "life of...". Look at all the people who follow celebs.

Course guess you still have to wonder, as far as porn surfers, how many do read. From what I've seen quite a few.

I usually read the first page of a thread before I post, at least.