I see a new feature on any login page for Stack Exchange sites called Log In With StackExchange. I wonder why this was added? I thought that OpenID was deemed a better plan and the whole thing was dealt with and no need to put more work on it.
The SE login still uses OpenID -- Stack Exchange is beta-testing acting as an OpenID provider:
The experience has never been really stellar. You click a link, end up on a new page on a new site, with Stack Overflow (or Stack Exchange) dwarfed by MyOpenID's logo... it's a tad confusing for the not so tech savvy user.
To this end we're introducing
openid.stackexchange.com, our own (beta) OpenID provider.