Turns out Blizzard is actually fighting Valve over the Dota name:
http://ttabvue.uspto.gov/ttabvue/v?pno=91202572&pty=OPP&eno=1
Trial Schedule:
http://ttabvue.uspto.gov/ttabvue/v?pno=91202572&pty=OPP&eno=1
Trial Schedule: