I don't even remember the name of the server or software, but even back when WoW was contemporary I had a lot more fun playing on free servers with extended XP, even though pretty often bosses would be buggy or not quite the same as in the real game. It was so much more playable and casual compared to the early WoW (or worse, EverQuest which came before). It's a shame game companies can't find a way to embrace or even profit from these kinds of servers.