@xj9 CouchDB is awfully sketchy with their continued use of MD5.
The reason to use a cryptographic hash function like MD5 over a non-cryptographic hash is so that you can write code that ignores the possibility of collisions. Once the cryptographic hash function is broken - as with MD5 and SHA1 - that's no longer true. That broken assumption almost certainly creates bugs, and they're probably security bugs that allow users to at least corrupt your data.
ferrus.net is one server in the network