Some years back, I asked the members of the DIYstompbox forum (who numbered well over 30,000 at that point, what generally drew their attention to a thread: the topic, intriguing header, who else is responding to it, number of replies so far, recency, etc. Many people said that there were a few long-time members whose participation (and visibility as the most recent post on a thread) frequently drew them to it. I know that one works for me. Even if the topic doesn't interest me that much, if so-and-so has posted in it, I think there's a reasonable chance I'm going to learn something if I check it out.
We're not nearly as bad as some sites, that seem to specialize in juvenile trolling. But at the same time, there are many threads here that have no illusions about being instructive or helpful. That said, as long as one sticks to certain sub-fora, the "I wonder what he/she has to say about that" strategy seems to work.