Site Sign Up, Sign In with Twitter and Facebook

I'm developing a website where the u开发者_运维问答ser can either sign up creating his own profile or can sign in with FB or Twitter.

The thing is I don't really know how to manage it, for example: let's say my user signs up through the website and creates content, what happens if the user later decides to sign in with FB or Twitter? How can I keep it all unified?

I know I could just do the Twitter sign in, get the data from twitter and create a profile in my DB for the user with his Twitter handle, don't know how I'd deal with later if he wants to just log in through the site.

Anyone have any ideas?

So he later signs in with Twitter or Facebook. I think you have a couple of options in this case. Allow the ability to link accounts together once the user signs in with any one method. Say they sign in with your sites registration, let them hit a page where they can add in other linked accounts like Twitter and Facebook once they are in their logged in state on your site. See the friendfeed model for inspiration. Or, like we did with ucubd.com/index.aspx - let the user sign in with facebook and regsister an account on their behalf and ask for their email as the login credential. If it's found - great. If it's not ask for a password. This will allow the user to either login with your sites registration method or through facebook. You will have the information in your database to link both of them together.

Every account on your system will have an e-mail address. Every account with FB, Google, Twitter is also linked to an e-mail address. What you will need to do is link the accounts based on e-mail address. That way you will never get duplicate accounts.