Yes, exactly. I was noting the amusing fact that Dropbox uses S3, but using S3 alone already offered exactly the functionality they're launching today for less money. Dropbox is adding is a brand name and an easier-to-use GUI.
Agreed. The difference between "how easy it is to share a link on S3" and on Dropbox is a million miles. Sure, actually sharing the link on S3 is easy, but getting the file onto S3, setting up security buckets, yadda yadda is non-trivial to low-tech users.