Originally Posted by gateswi
Is there any permanent kind of experience accumulation that would make this like an mmo?
Sort of yes. When you create your account it, the account is level 1. You can choose different heroes to play in your matches. During the course of the match your hero levels from level 1 to level 18, win or lose your hero always starts a match at level one.
But your account levels up slowly from level 1 to level 30. You get your xp for playing, win or lose (more for winning). As your account levels you open a talent tree (like world of warcraft), and can choose to specialize in some general things.
You also open up a rune book, which lets you "equip" stat bonus type buffs.
You also gain access to different summoner spells. Besides the spells/abilities the hero you choose has (everyone has 4 different ones) you get to choose 2 summoner spells before the match. These are mostly utility type spells.
That was probably clear as mudd.