I have not done more than look at it so far but I heard good things about it when it was still called Syncthing. As for making money off OS code there are a number of companies doing it (Free code + paid services). BTSync could offer help to enterprises setting it up internally, they could offer a cloud to sync your data to (encrypted), they could offer pro-features (like some stuff Dropbox offers). The whole point is that it needs no central server but the sheer existence of an API key means there IS a central server that this all relies on...