I'm also confused about who this service appeals to. Flickr is incredibly popular across a whole age range, and was pretty much built around sharing and tagging

I'm also confused about who this service appeals to. Flickr is incredibly popular across a whole age range, and was pretty much built around sharing and tagging photos. Most people who want to share photos but don't know (or care) about flickr will simply create a Facebook photo gallery, which is limited feature-wise but dirt simple to use. If this site had a facebook app it might be able to reach those users, but third-party applications seem to be loosing prominence since Facebook's UI overhaul last year.