Facebook is getting ready to open its stream up to third-party developers, which will allow for a ton of new Facebook-related applications, that won’t have to be used from within Facebook. According to the Wall Street Journal, developers will be able to access photos, videos, notes, and comments from the Facebook Stream with users’ permission.

This is one area where Twitter has excelled, and Facebook likely knows this and does not want to risk losing users to the more open network. In fact, the WSJ’s sources say that Facebook is looking to build user loyalty with this move.

Twitter’s APIs have allowed for third-party developers to create numerous useful apps like TweetDeck, and our own Twellow that enrich the user experience with Twitter, making it ultimately more useful. Now we can expect a similar scenario with Facebook.

Developers will reportedly not be charged, and more details should emerge today, as Facebook is expected to discuss the news at a developer event in Palo Alto.

It’s going to be really interesting to see the types of applications that developers come up with. The move is sure to take Facebook up another several notches in user engagement. For those who already spend a tremendous amount of time interacting through the social network, more ways to do so will only solidify Facebook as the leader in social networking.