Dungeons & Dragons Online did it. Lord of the Rings Online is doing it. More and more massively multiplayer online games are switching to a free-to-play model, but none quite as fast as Hi-Rez Studios' online shooter Global Agenda.
Launched in February of this year, Global Agenda was to have two different pricing tiers. Players could purchase the game and play forever, subscription free, with certain content restricted to those who chose to shell out $12.99 a month.