This was just posted in Facebook today:
Our race engineers have been hard at work and were now ready to announce the availability of both the multiplayer and Classic Edition content for F1 2013 for Mac.
Cross-platform (Mac vs. PC) multiplayer for up to 16 players will be supported in all copies of the game (boxed and digital) with SteamPlay. These will be available from the Feral Store, Steam and other third-party store partners. A Steam account will be required for both activation and online play.
Copies of the game purchased from the Mac App Store do not support SteamPlay and will be single-player only.
F1 2013 will be available as both a standard edition and as F1 2013: Classic Edition, a premium version of the game that includes all additional content. To find out more about the additional content, visit the Classic Edition page on the F1 2013 minisite.
http://www.feralinteractive.com/en/mac-games/f12013/classic-edition/