If you don't know what it is, just move to the next thread or check out
wiki.
From time to time, I play DotA so I was wondering if anyone here is playing it too..
Oh yeah, its too much time consuming so I don't recommend you starting with it.. I even registered
http://quitdota.com 
I also have
DotA related site (PR3) so if anyone is interested in buying it or developing together with me, hit me up