Once upon a time the greatest video game in history, Warcraft III, was released. Included with the game was a powerful "World Editor" which allowed players create their own gametypes. These custom games provided a haven for the 30-apm ladder dropouts.

Dota, a game where players managed a single hero and no base, was the most popular and best-supported of these customs. Eventually there were a number of attempts to monetize on its popularity.
League of Legends, or LoL, was arguably the most successful of these attempts. The game was developed by dota's former developers and borrowed heavily from its predecessor. Introducing the game via a free-to-play model ensured millions of broke teenagers would download it and get hooked. Then later, when they received birthday money or just stole their mom's credit card, they could spend much more than a standard $40 game price unlocking game content that would have been free under a conventional system. To ensure the game would have universal appeal, riot removed game mechanics that punished the unskilled, such as denying. The base income was increased beyond even "easymode" levels compared to dota so that all players would have gold to spend, and item guide railroaded players into the best items.

A gaming site where trolls get trolled.

this game is from the original creators of DotA(Defense of the Ancients) a Warcraft 3 expansion.

Riot Games are the creators. This is a free to play online game that has an in game store that you can spend real money on if you wish to. You can not purchase "runes" because they are to be earned through game play so the rich and poor are at the same level of skill while playing.
Actually if you buy the Collectors pack it comes with a few runes.
The game name is shortened to LoL.
Again it is a free game.

A game so addictive and stupid, that you cannot quit no matter what. It is filled with 13 year old rage hard noobs who think they are the best, yet they feed and call roles they can't play for shit.

This game also consists of a rating system that is equivalent to a 1v1 match, but the catch is that it is a team game of 3v3 and 5v5. No matter how hard you try, carrying noobs in this game is almost like taking a shit while constipated, its not going to happen. Unless you are like extremely lucky. ELO Hell is the place all the baddies go cause they suck,and where the some goodies go cause the baddies couldn't be carried. ELO Heaven is where all the non-baddies go.

An extremely popular game that now has more players than World of Warcraft.

Although it is free, so perhaps that's not as big an accomplishment as it sounds, but free or not, many people pay money to get skins for their favorite characters. Anything you buy with real money besides skins, you can get with the in game currency as well, so there is no disadvantage on people who don't pay.

The genre is hard to explain, but is a somewhat rare one, known as a MOBA. This means Multiplayer Online Battle Arena. The goal of the game is to fight your way into the opponent's base and destroy their "Nexus". I put it quite simply, but the average game takes around 40 minutes, and has quite a bit to it.

This game has an extremely huge learning curve of anywhere from 2-10 hours for most people, sometimes more. In order to become good at the game, it takes several weeks, although it is more casually oriented.

For those not interested in casual play, this game was featured at Dreamhack with a $100,000 USD prize pool in June 2011, where several teams fought in competition for the prize.

It is a very fun game, but not something many people can just pick up.

An extremely crappy game made by some gay jerks in Mongolia. There are a lot of players but I don't know why because the game is even worse than yo mama.
So the game basically just sucks hairy penises.

A game created by Riot games. Essentially, it is very similar to DotA (Defense of the Ancients). It is free to play with some pay features, however there is no need to pay, the only benefit is like new clothes for a character than gives no stats or anything. Runes are gained in leveling so there is no unfair advantage for the richies. Free to play and essentially a good time.

A game based on DotA, developed by Riot Games. After its release, it became very popular (being a free game helped at that), and has earned a place in MLG and other eSports.

Correcting the other definitions, Riot Games did not make the original DotA in Warcraft III, they just modded the DotA map that was created by Eul.