I realize these are companies and they have to compete with proprietary features, but it really bothers me that Dropbox, Google Drive, SkyDrive, etc. are all us

I realize these are companies and they have to compete with proprietary features, but it really bothers me that Dropbox, Google Drive, SkyDrive, etc. are all using their own proprietary technology for the basic sync. It really does bother me that a company that was born on Hacker News has yet to open source its sync tech.