Jake is an interesting twist on file syncing and sharing apps, in that it uses XMPP as transport and embodies a concept that I and a few of my colleagues had been discussing a couple of years ago but never got round to implement (probably because I tried to get rsync into the mix, which would be nice but too complex). Unlike Dropbox, it has no requirements for a central server – only for an XMPP server to act as meeting point and reflector.

Sadly, it is written in Java, which makes it cross-platform but finicky.