 Valve 's interest in the Defense of the Ancients property began when several veteran employees , including Team Fortress designer Robin Walker , became fans of the mod and attempted to play it competitively . The company corresponded with IceFrog by email about his long @-@ term plans for the project , which culminated with his being hired to direct a sequel . IceFrog first announced his new position through his blog in October 2009 , and Dota 2 was unveiled by Game Informer on October 13 , 2010 . The resultant surge of traffic crashed Game Informer 's servers . 
