How to recognize if your site admin is using (claims-based authentication)
This one’s pretty easy – as soon as you enable claims-based authentication in SharePoint 2010, it attaches a coded ID to all the usernames that looks like this: i:0#.w|contosousername. This coded ID looks like a weird error to the uninitiated, but not to you – oh no! You know what it all means and are able to decrypt it using the following handy-dandy decoder ring:
Take it easy, man… claims are fun!
From what I’ve been able to learn about it, claims-based authentication has some interesting possibilities that make it worth exploring but has a few major gotchas. For instance, once you’ve transitioned to claims-based authentication, it’s a one-way street – there’s no going back.
Basically, as with any technology changes, if it’s set up properly it has a lot of new and shiny things that you can do – if set up incorrectly, it will cause a lot of headaches and will have you either blowing your application away and re-creating it, or restoring from your latest backup.