Just because people don't post doesn't mean they don't benefit from being members on the site. There are very different levels of comfort with interaction on web forums, and while this is a particularly welcoming one, many people may be more comfortable with reading posts and learning than with being an active member. People have different objectives and different ways of interacting on line just as they do in person. I am a member of other sites where I rarely post, but I would hate to be removed from them because I do visit them to learn.
just my opinion,