I think its largely a regional thing, I've been in Twin Cities and it wasn't huge, social anarchism was bigger, but in Portland a lot of the regulars consider themselves nihilists. It might be the age of the the anarchist movement here and the proximity to Eugene and Olympia where primitivists and anarcho punks (rather than social anarchists) held down the movement from the end of the new left to the start of the alter globalization movement.