So how does the Steam Web page run on an android or an an iOS device?
While there might be some cross platform games like the current mac+windows games, I would expect a store app on there if smart phones have any problems with the store page. Someone out and about, either through conversation, seeing an ad, or even checking one of the constant sales on steam and thinking "Oooh, I gotta get that!". With a Steam Store app, they can buy the game right then and there. I could even imagine If they happen to leave their home PC on, with the proper settings, it would see a new game, and start downloading for you.
While I was on vacation last summer, I remember trying to snag a wireless signal so I could check the daily specials, and got my favorite Steam purchase so far: Borderlands + first 3 DLC for $20.
