There's still yet another side to it. Wolfenstein: Enemy Territory is still around today. Boot it up, and try joining a game. Five hours later, the mods finish loading, and you get a splash screen full of ads before you begin playing with bots.

At the time, it felt like there were a lot of hobbyists willing to shell out cash to run their servers, but ensuring you got a fair game low on mods was often more trouble than it was worth. I'm even a little bit grateful that Team Fortress 2 started hosting their own, even if they failed to fix the bot situations.