You can click on the Google or Yahoo buttons to sign-in with these identity providers,
or you just type your identity uri and click on the little login button.
For the record, there is also a similar service at http://www.faviki.com.
as far as I know, faviki uses commontag.
Ticket #502155 - latest update on 2010/02/16, created on 2009/10/31 by Nicolas Chauvat