Maybe we shouldn't tell them to post, but ask them why they aren't posting, there could be a reason. I remember on the old board a thread like this was started before I used to post, the reason I didn't used to post was that I always felt like I would be repeating what somebody else had said.
Don't feel that you shouldn't post, just because somebody has already said something similar to what you wanted to say, saying it is still worthwhile.
just my 2 cents...
jonny