ApocTV

Blizzard has decided to sue Valve for using the "DotA" name.  According to Blizzard,  "The DotA name for more than seven years has been used exclusively by Blizzard and its fan community, under license from Blizzard." DotA (Defense of the Ancients) was originally a custom fan-made map in WarCraft 3.  For DotA 2, Valve hired two of the original creators of the WarCraft 3 map (IceFrog and Eul) and trademarked the name DotA to use for their upcoming MOBA game, DotA 2.

Source: http://ttabvue.uspto.gov/ttabvue/v?pno=91202572&pty=OPP&eno=1