I spent some time learning about PouchDB a little while ago, it seems to be a nice solution at least for a No SQL approach. Although I still need some more practical experience to understand the security model, because it feels weird to just sync a database that was updated on some web page, really you want to ensure there is validation and treat it as an untrusted source to some extent. Still not sure of the best way to deal with that without implementing most of the application as server side validation scripts, or maybe that is just the way to do it.