Hmm. I guess I messed up something with my old 25GB SkyDrive account because if I use my other 7GB SkyDrive a link to SkyDrive shared files doesn't allow me to go back but the old one does.
I haven't tried sharing an entire folder on my new 7GB SkyDrive yet. I guess I should try that too.
@dentaku: I agree that it would be nice to see file extensions in the list, but they are displayed in the details pane.
I was just working with a folder shared from my sister for my parent's 40th anniversary, and I was not able to browse up her folder tree. The folder shows up in my Skydrive under "Shared".