As far as I know, cloudant's product is BigCouch which was a fork of CouchDB but has recently been merged back in:
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.