An interesting argument from Farhad Manjoo about why Dropbox is a hard sell as a disruptive business:
There are two reasons for this. First, the perfect syncing service needs to do more than simply store files. Second, the perfect syncing service should be unlimited and free, or as close to it as possible. Dropbox will have a hard time doing the first of these for technical reasons, and if it does the second, it won’t be a very good business.