Apache CouchDB is the original opensouce project. The guy who started it left a year ago (?), but the project is alive. How much so? I don't know..

Membase does not exists, it was renamed to Couchbase Server. It used to be CoucbDB + Memcache, which seems like a strange combo to me, but I haven't tried it. Also, I guess it has evolved since then. According to wikipedia: "It has a separate and independent community, provides a very different set of capabilities, and supports very different use cases".

CouchDB still looks interesting, it "more different" than many of the other nosql databases. But you might have a hard time building Facebook with it: https://lists.ubuntu.com/archives/ubuntu-desktop/2011-Novemb...

For me, that's not an issue :) Also, the release notes says it has a "new replicator", so ..

http://en.wikipedia.org/wiki/Couchbase_Server http://en.wikipedia.org/wiki/CouchDB