The major one is that their price point just seems too high. $99 a year just isn't a price that I'm willing to pay without seriously considering the value I'm getting. (Then when I consider the value, $99 can buy a pretty big portable hard drive or flash drive. So I buy the drives and just use the free 2 gig Dropbox for synchronizing smaller files.)
On the other hand, I had no problem paying $30/year for Flickr Pro. That's an easy price point, even for a cheap bastard like me.
The minor one is that they don't seem to own dropbox.com. I don't know how that didn't get done before settling on the name, but they gotta get that cleared up.
As for syncing and sharing project files, that is what the git repository is for.
But quite obviously there is a market for what they sell. I'm just not in that market. Not until I can get half a TB for my $99, anyway.
Flickr's been an somewhat easy way to back them up and share them at the same time. But I have growing frustration with Flickr because I'm really using it for three different purposes now: backing up all my photos, sharing family snapshots with friends and family, and sharing more artsy photography with mostly strangers (which is really Flickr's sweet spot).
Using Flickr for backup is incredibly annoying and iffy because their uploaders are so fragile and downloading the entire collection depends on third-party software that Flickr could break or disable at any moment.
I'd love to move my photo backups off of Flickr and am close to using just some rotating USB hard drives, but I'd much rather have something automated. Dropbox could definitely have my business there and be price competitive if they offered say 250 gigs for under $100 a year. Backing up my photos should be a good profit for them over time, because once I get past the initial backup, I really only upload a gig or two a month and rarely download. Unlike my other documents, I don't need my photo backup replicated between my different computers running Dropbox.
Sharing photos with friends and family is something that Dropbox could be good at or at least acceptable. The Flickr, Picasa, and Facebook uploaders all suck compared to the ease of Dropbox. If they added some better privacy settings, RSS feeds, and some more viewing/downloading options, they could be player in the photo sharing space.
Amazon S3 (some consider it wholesale) would cost you 3 times that, and that's not even considering in/out bandwidth charges or Dropbox's nifty client and version history (which lets you, for instance, restore "deleted" files).
All I am saying is adoption will rise if the price point drops. Right now it is high enough to turn off price-sensitive individuals.
(Guy's too polite to come toot his own horn here.) Might fit your use case, if you're willing to trade shine for price-efficiency.
No, you're right - my basic arithmetic comes out with the same number, now that I've checked it. Good catch.
I assumed (thwack) that, since 'tarsnap' is only taking a small premium over Amazon S3 charges for real use, it would always be a better price. Wrong (thwack), if you do have between 30 and 50 GB.
Possibly Dropbox can beat the price because the buyers of the 50GB plan use less than half, in average. (Leaving aside considerations of Amazon vs. dedicated infrastructure costs.)
For people with the need for more storage there is a 100 GB plan I think...
Personally I would have just chosen a name that isn't already taken.
Would you prefer them to use a name like droppboxx or drropbox instead? Most likely some domain squatter sat on dropbox.com and demanded 3 million for the name. They could have picked a completely different name, but dropbox is nice and simple, and the correct site comes up on google which is what most people use anyway.
With google toolbar installed, all it takes is to enter - drop box - on the address bar, anyway!