Just launched droppr - What bit.ly is for urls, droppr is for files.

Your sign-in dialog does not explain the value of signing in, this comes of as your customer database building tool more than anything useful to the consumer, I'd think you may want to clarify that bit there.

Couldn't find any limitations to the time of file storage, are there any? If no, how do you plan to scale and monetize it?

Sleek interface, what's the backend coded with?