OAuth 1.0 is mix of authentication problem (as solved by HTTP authentication) and connection protection problem (as solved by SSL) and cross-site authentication problem.

OAuth 2.0 is mix of authentication problem (as solved by HTTP authentication) and cross-site authentication problem.

I hope, OAuth 3.0 will solve cross-site authentication problem only, so I can use standard HTTP or cookie-based authentication solutions and standard HTTPS protocol (when necessary).