Starting March 11, when iOS 4.3 launches, users will be able to stream content from third-party apps on the iPhone, iPad, or iPod Touch to an Apple TV. But so far, the scope of support for the functionality is very much up in the air.

Music-video site Vevo is one of the few companies to acknowledge that it's ready to take advantage of the new AirPlay functionality. The company added support for the feature on Wednesday to its iPad and iPhone apps.

But unlike Vevo, Netflix doesn't see the benefit of adding support for Apple's new feature, and won't offer it in its iPhone or iPad apps, GigaOm reported yesterday.

Netflix Vice President of Corporate Communications Steve Swasey pointed out to GigaOm that "Netflix is already available on Apple TV." Rightfully so, Netflix believes that adding AirPlay support to its mobile apps is rather useless, since Apple TV owners can access its content from the set-top box without the need for other devices.

However, Apple's upcoming AirPlay functionality could be a boon for other app developers that want to bring their content to the Apple TV. The only question now is whether those developers will follow Vevo's lead and see value in it. At this point, it seems many companies are still trying to decide if the functionality is right for them.

One of those companies, according to GigaOm, is HBO. Citing an unnamed source, the publication said HBO is considering the possibility of using the new functionality, though the source didn't provide any details.

HBO support for AirPlay would be quite a surprise. The cable network is notoriously protective of its content and so far has been reluctant to see it made available anywhere else, especially on Netflix's streaming service.

Over the past several months, HBO has commented several times on its issues with Netflix, saying the streaming company charges customers too little. Back in January, Jeff Cusson, HBO's senior vice president of corporate affairs, went so far as to say that the company "has no intention of making its content available for streaming" on Netflix.

However, if HBO opts to stream content to the Apple TV through AirPlay, it could circumvent Netflix, effectively bringing its content to the television without having to ink a deal with the company it has taken such issue with.

But HBO is just one of many companies' in the coming weeks look for more to announce their plans to either support or ignore AirPlay.

Further reading: New features in iOS 4.3 (photos)