Does it matter? Surely everyone has different reasons for using the forum? Some post once to say hi and then go back to lurking, some post regularly but specifically Subaru related and some see it as a social environment for chat and banter. It's all things to all men and that's the beauty of a forum - Facebook, twitter et al have to be one or the other - a forum is whatever you make of it.
My one small point would be to make more use of the search tool and look in the suggestions thread before making suggestions - it's hard for us not to come across as negative when we have to say "tried that", "suggested that last year", "we did that but nobody used it" etc
Personally I think that as a member, it's your forum to be used as you wish (within reason, for the benefit of other members). Everyone will have an opinion but as long as you're doing what you feel is in the best interest of the wider community, why should it matter how frequently or infrequently you post? After all, the forum is only one small part of the club.