A question that remains unanswered for me is how do they go about storing the local data in the browser? Do they use local storage? Are there size limits? What's reliability like?
BigCouch, and the clustering abilities that we're merging back into CouchDB, are open-source artifacts of the work we do on the core product. The open-source community gave us so much, and we love giving back :D
And I think it's great that BigCouch is being merged back into CouchDB. I'm just getting interested in CouchDB and PouchDB and it seems these projects deserve the love.
Ah, PouchDB isn't our product. It's just something super awesome that we want to support and promote. In fact, it's built by Dale Harvey, who works at Mozilla.
Disclosure: I'm a developer at Cloudant.