OAUTH- an application which is also known as Open standard for Authentication. like it's name, it is used for authentication in other websites, it is used for acting in your behalf like posting, sharing pictures and other stuff which is stored on one website. i.e. you share a photo in 9gag to your facebook account.


OAUTH is complementary to OpenID but completely different to it.
on OAUTH, there is what you call OAUTH protocols for different sites/service provider,
like facebook and it's corresponding protocol -2.0, tumblr -1.0a and so on and so forth.


BrowserID- this one is built by and for Mozilla
this is similar to OpenID but has certain distinctions/features it uses email addresses as an identifier, it is focused on privacy, and is intended to be fully integrated in the browser