Why Are MOBA Games like League of Legends So Popular?

Multiplayer Online Battle Arenas, or MOBAs, refer to a very specific subset of top-down, team-based strategy titles. Despite humble beginnings as a modded offshoot of real-time strategy games, these titles have exploded into the forefront of PC gaming, gaining tens of millions of players and a spot at the top of the eSports (blech*) world.
by Michael Crider via How-To Geek