Apparently Apple is not only the least scared but has also come forward to offer minor help to Facebook with their secret development called Project Spartan. Facebook's new HTML5 web app platform to rival Apple's App Store has been reportedly called an attempt to break the stranglehold that Apple has on mobile app distribution.
According to aTechCrunch report Apple has knowledge of the Facebook project and has lent some minor support to its development. The report said that according to people familiar with the matter Apple is not afraid of [the project] at all. Having seen some of the early Spartan apps, the likelihood that users would choose them over a native iPhone app is laughable, it said.
However the report said that Apple doesn't have much idea of the full scope of the project and about Facebook Credits monetization aspect. I believe the main reason Facebook is pissed off about our Spartan story is this part in particular, wrote M.G. Siegler. Apple may not view Spartan as a threat at all right now - and in fact, it sort of helps them because it is moving popular games, like the ones by Zynga, off of Flash and onto HTML5 - but down the road, that is absolutely what Facebook intends it to be.