One of the first things one learns about when studying computer networks is the bad old days of sneakernet, where people would physically transfer data by using removable media. LANs were supposed to solve all that.
But in the real world, I often find colleagues and friends sharing data by using USB flash drives. These are not computer neophytes, but engineers and software developers. They find it a lot easier to plug in and plug out, than it is to mess with domains and set permissions, or to email an executable (it's blocked by the mailserver, so it has to be zipped first, or have its extension changed).
Someone already wrote an article on this in 2002.
