Dont really know, its never struck my intrest.
Heck, I've never been on the test server to be honust but I have thought about it.
I would imagin the population is pretty goo there however, as for the economy?
Couldnt even begin to guess.
If your wanting to know, best thing to do would be to get a charecter on the test server, it dosnt count towards your charecter limit.