We already have too many usernames and passwords! Please don't contribute to "account bloat." Especially given that you already support Google+ hangouts, letting people use their Google [or other service] accounts for authentication seems like a natural step.
For more information, see <a href="https://developers.google.com/accounts/docs/OpenID" rel="nofollow">https://developers.google.com/accounts/docs/OpenID</a> .