yay for slow Libyan internets >_<
I don't think that, over the past couple of years,
ZU has grown VASTLY bigger, no. So, I don't think that's a factor. There is always a core active membership of a couple of hundred who are active and shaping the identity of the forum.
Time and quality are two seperate entities, especially when by "quality" you're talking about people. Sometimes, quality remains high through time - which is an indicator of its quality. if quality deteriorates over time, it's not time's fault, but the people's standards.
I had a wee look, and I can understand what you mean, and yeah .. quality is a bit lacking. And I still believe it has to do with who the core active members are and their "branding" as it were.