Mudcat has been a major part of my online existence for nearly two decades. I too first posted in 2001, although I'm taking a break at the moment having become disillusioned by the bear pit that below the line has become and which seems to have a meanness about it that I don't need in my life at the moment. It was ever thus in a way, but it seems I don't learn much now whereas I used to learn a lot from people I never would have met otherwise. Some of my most fundamental views were challenged and altered as a result of these discussions.
I learn lots from above the line, especially in the early days as a fledgling bouzouki player seeking advice and the kindness and generosity of folk got me off the ground. The Cat was a place you could ask beginner's questions without being treated like a dullard, and this continues to this day.