Here's my take on it: CouchDB: Still there, still doing their thing but now as an Apache project. A few companies have built businesses around it such as IrisC

Here's my take on it: CouchDB: Still there, still doing their thing but now as an Apache project. A few companies have built businesses around it such as IrisCouch (SAAS platform) and Cloudant (who maintain the open-source BigCouch which is API-compatible with CouchDB but adds more scalable clustering). CouchBase 2.0 (née Membase/CouchOne): Basically a version of MemBase (which was developed by the memcached developers) with some of the engine parts and concepts from CouchDB mixed in. My understanding is that a lot of things were also written from scratch. The idea is that it's the best of both worlds: good in memory dataset performance, disk persistence, data replication, cluster rebalancing and partitioning. Not sure how it works in practice. The name is a bit unfortunate because it appears to be more like memcached from the developer API perspective than CouchDB. If successful, I don't think CouchBase will replace CouchDB but it will instead carve out its own place in the ecosystem.