As AdMob or iAd is not yet available on Mac, how can we add ads to Mac Apps? Is Adsense allowed? Or is there any other available ad platform? Thanks.
BuySellAds.com has a Cocoa framework for embedding ads in Mac applications. AppBodega appears to be among the first applications to use this for in-application ads. Mac.Appstorm.net has a bit of additional information on this.
Other Mac applications use ads from The Deck (invitation only) or Fusion Ads (again, fairly exclusive).
While there is no guarantee that anything will or will not be accepted for the Mac App Store, there are no explicit restrictions regarding advertising in the current published guidelines. You do need to obtain consent before transmitting any user-specific information, but that may only impact any analytics data you gather.