OAuth 2.0

To add, I would ideally like it to be permission-based a la Twitter, Google, Facebook, etc... so users can see what things they're authorising and for developers to target individual services. For example, an application which wants to view the contents of your vault probably doesn't need to be able to post to the forum. In saying that however, I think it's pertinent to recognise the inherent danger in third party applications having access to accounts (especially those which modify in-game elements) along with the susceptibility of players, especially younger ones. As most people here have no doubt seen already with what happened via Playstation's Share Play, some players will go to lengths to achieve what they think will give them an/the edge, even if it does mean cheating. So if they see an application which can do it for them (or at least claim to), I have no doubt some will try to use it. I still don't want to say I don't support the idea (obviously), but setting it up in such a way that allows third party applications to be deployed while communicating to players what the potential risks are of allowing them access is crucial.