[igotrhythm]

On top of there being competitions for it, there /is/ a fair amount of physical conditioning involved, as well as necessitating detailed study and practice of various situations.

However, insofar as you can't actually do much to affect the other player's performance in most tournament formats, it's not a "sport" to some. However, gymnastics and other "performance" sports (diving, etc.) break this rule wide open.

So yeah, I'd say it's a sport if DotA and SC can be considered sports.