Bioshock Infinite is a Steamplay title, which means it will activate on the systems the Steam listing shows... So it's always worth checking the game's Steam page if you are unsure :)
cheers fuzzle, it's good to know :)
If it's a steam key it's usable on either platform as long as it's Steam
I'm guessing as it's from the 'Mac game store' it will only run on mac? not 100% sure though ;)
Will the steam key work on Win OS or is it just specifically for Mac?