Think long and hard before you implement something like this on your website. Implementing the bog-standard login system is a one-morning task for any engineer capable of writing a web app. Supporting multiple logins well can occupy teams of competent developers continuously and they will still screw it up. The underlying OpenID/etc protocols are some of the worst designed you will ever have the misfortune of working with. Your users will hate the experience of using them on your site, largely because a) they do not understand them, b) they do not solve a real user problem, and c) when you screw up your implementation -- and you will -- you will lock them out of their accounts.
I might be part of a minority, but I love websites which let me sign up with OpenID/Twitter/Facebook. No need to fill out the same registration forms over and over again or having to wait endlessly for confirmation emails. Moreover no need to remember which username/password I used for which sites, etc.
I don't see anything in the GITkit documentation where Google promises any kind of uptime number or notification window before disabling the service and leaving you with no way† for your users to authenticate to your service.
† You could try get them to do a password recovery procedure since you kept their email address, but I'd rather not send out an "I'm sorry, we lost your password." message to customers.
Perhaps a little premature post: looking at http://accountchooser.com/how.html (as of 8/29 at 12:23pm) there are a host of "image coming soon" placeholders. At least finish up your first sentence before broadcasting.
The site is going fairly unresponsive, is this a login service like Janrain RPX or is this more akin to a component that you integrate yourself, like AuthLogic?
Tried signing in to the "Sample Store" on the site using Gmail, but the attempt merely resulted in a blank popup window on Firefox 6. It's a shame because it looked quite promising until then.
I got a little past that, up to a perpetual "Signing in" progress ticker.
(After refreshing, I could verify that I was not logged in, but I'm not sure if the demo was supposed to go as far as managing session cookies anyway.)
