A few days ago in the Dropbox forums, a developer said Apple had rejected his app due to a little quirk, so to speak, in using Dropbox. Specifically, if a user doesn't have the Dropbox app installed, a link to a web page would be issued, causing the user to go to Dropbox's website or a mobile version which would allow them to log in. That's not the problem. The problem was that this web page contained a link that could eventually lead to a