Comparing MMO online presence to FPSs is comparing apples and oranges. MMOs are designed to keep you playing for hours upon hours; FPSs, though some do the same

Comparing MMO online presence to FPSs is comparing apples and oranges. MMOs are designed to keep you playing for hours upon hours; FPSs, though some do the same, are structured in 5-15 min individual games. And all that time is spent playing, unlike MMOs where boring downtime spent chatting can dominate the experience at the upper end and in some games (like EVE).