It isn't simply a factor of age and community size.  A few years ago I was picking up both python and php for the first time for a couple of projects and as such spent a lot of time on both comp.lang.python and comp.lang.php (I said it was a few years ago).  Both groups where roughly equally active, and both languages roughly equally old.  Yet those two groups couldn't have been more different.  In the python group people where, on the whole, polite, asked advanced question and got detailed answers.  In the php group people where often insulting, the questions where almost always trivial and still the answers a best shallow and at worst completely wrong.