It has been clear Dota has changed the esports scene and maybe more than many of us realize. Especially with Dota 2 it has been one of the biggest games ever. WCG which had been hosting tournaments for about 13 years talks about the importance of Dota 2 which is interesting because I never really thought about it before. They talk about it here.
They outline some history I was not even familiar with it's pretty cool:
Dota 2 represents the genre known as MOBA, AOS, or DotA-like that was born out of the user customization mode of RTS games.
The genre was born around 2002, out of the StarCraft user map ‘Aeon of Strife’ made by Aeon64. This user map contains all of the basic components that still live on in the MOBA genre today, such as three-lined battles, friendly and enemy forces that are automatically generated, and the concept of gaining victory by destroying the opponent’s main base.
A team-play user map made by Eul appeared in Warcraft III. This type of map evolved into the Defense of the Ancients (DOTA), the first mod of the Dota series, which also ushered in the MOBA genre. Dota quickly became popular for the high quality and playability of its user maps, and many games and mods were developed based on Dota’s maps and data.