http://baboonmetaphysics.myopenid.com/ created the issue

Dropbox is free online storage (max 2GB), with its own client which automatically synchronises between the server and a local folder. The space is actually hired from Amazon S3 (already supported). Software these days should do one thing and do it well; I feel it is unnecessary that Dropbox should have its own client, when there already is an existing excellent standard for Mac.