>> 1. For a Linux user, you can already build such a system yourself quite trivially by getting an FTP account, mounting it locally with curlftpfs, and then using SVN or CVS on the mounted filesystem. From Windows or Mac, this FTP account could be accessed through built-in software.

This type of response is so typical of an engineer and so out-of-touch. Not to pick on it, but it's just absurd, and shows zero ability to put oneself in the shoes of the layman. And yet these types of responses are all over the tech community. This disconnect is the exact reason someone like Steve Jobs is able to enter product categories very late but still blow away the competition.