OpenId/Custom Hybrid Authentication - Bad UX?

I'm designing a new web application. Some quick points on it:

• ASP.NET MVC Web Application
• SQL Server 2008
• Entity Framework ORM
• 3 User Roles: Anonymous, Registered, Administrators.
• Anonymous users can view stuff, Registered Users can post stuff, Admins can do anything
• Heavy social integration with Facebook, Twitter and the like.
• I plan to use OpenId for authentication (DotNetOpenAuth)

So, pretty simple right? (famous last words)

Now my question is:

Should i provide OpenId as the only means of authentication, or should i also give the user the option to log in using my own authentication system?

So this is basically a "User Experience" question. Take the example of StackOverflow - you MUST signup with OpenId. It seemed fine to me, but what about the general public? Can i be happy with the fact that a user of my site must have an OpenId account? (or signup for one before using my site)

Is giving the user two options to login bad UX?

I realize this is a partially subjective question, but im just looking for advice on which road to take, some case studies would be helpful.

Th开发者_StackOverflowanks.

Any good answer to a subjective question begins with it depends. :-)

I think if your prospective user base is already fairly social-network engaged (as it sounds by your description), it will probably be just fine to have authentication handled by OpenId providers. The important part is providing an easy-to-use login process, and make it obvious that various providers are available for authentication (Yahoo, Google, etc.).

If your prospective user base is going to consist of new or inexperienced Internet users, even a simple OpenId implementation may be too confusing.

I, for one, find it annoying to have to create yet another account every time a visit a new website, and I suspect that more and more users are feeling the same way.

There's a decent set of responses to a similar question at https://ux.stackexchange.com/questions/78

The thing is that only OpenID won't cut it in you case mainly because of Facebook and Twitter who aren't OpenID providers. Both use OAuth 2 for authetication. Wikipedia says this about it:

OAuth (Open Authorization) is an open standard for authorization. It allows users to share their private resources (e.g. photos, videos, contact lists) stored on one site with another site without having to hand out their credentials, typically username and password.

and this:

OAuth is a service that is complementary to, but distinct from, OpenID.

The DotNetOpenAuth also supports OAuth and the latest CTP release implements the OAuth 2 draft 10. Mind you that the OAuth 2 specification is still being developed and is expected to be finalized by the end of 2010. OAuth 2 also isn't backward compatible with OAuth 1.