Really nice, but the thing is... Dropbox has gone beyond just file sharing. One example: I used to use Flickr for photo sharing, but cameras got better, images got bigger, and I have a lot of photos. I moved from Flickr to Picasa as it could cope with the directories full of photos and I didn't have to manually upload them and Google's storage space was cheaper. Then I ran out of space... over 100GB of photos, where…
Google+ does that too now, but this is in fact a killer feature which has been adopted well by the average folks out there. So yes, Dropbox is not just about file sharing anymore.