To me, it seems the ACA Forums are more ACA specific (duh) than the other cyclotourist forums. There is nothing wrong with that. I also subscribe to the Thorn Cycles Forum but it too has very low counts as it is mostly Thorn specific.
Also, a lot of the questions tend to be very very specific, i.e. "I need a route getting from the LA bike path to LAX", where the vast majority of readers are unable to provide a viable answer due to lack of local knowledge (even though some readers seem to respond to almost every thread even if their point adds nothing). A lot of the majority of the remaining questions are repetitive ("what kind of gearing do I need", "when is the earliest/latest I can do the TransAm?", etc. )
These are not knocks on ACA but just shows it is doing what it is supposed to be, that is, be the site to go to for ACA specific info.
If you want lots of comments, start a thread about panniers vs. trailers, Rohloff vs. traditional, hammocks vs. tents, or some other topic which should have been flamed to dust by now
. How about a thread on a guy wanting to ride with a trailer, Rohloff, and a tent vs. a girl on a traditional pannier hammock setup?
All in all though, I too wish more people participated.