I use Tarsnap and Dropbox. They aren't the same at all:
* You run Tarsnap whenever you want to push changes; Dropbox automatically pushes changes.
* Tarsnap is for 'real' computers only; Dropbox runs on my phone (which is very useful for photos, among other things).
* Tarsnap is billed by usage (at a very small amount); Dropbox has a free tier.
* Tarsnap doesn't have a natural sharing usecase; Dropbox does.
* Fundamentally, Tarsnap is backup, and Dropbox is sync. They are two different things. Not to mention that Tarsnap is also supported just fine on Linux.
* You run Tarsnap whenever you want to push changes; Dropbox automatically pushes changes.
* Tarsnap is for 'real' computers only; Dropbox runs on my phone (which is very useful for photos, among other things).
* Tarsnap is billed by usage (at a very small amount); Dropbox has a free tier.
* Tarsnap doesn't have a natural sharing usecase; Dropbox does.
* Fundamentally, Tarsnap is backup, and Dropbox is sync. They are two different things. Not to mention that Tarsnap is also supported just fine on Linux.