It is time for NoSQL community to come up with a standard key/value API. Is anyone working on it?
As one commented said "JDBC came out ~25 years after SQL was created.". By today's standards 2.5 years should be about right time to expect a standard :)
Maybe in the future Redis may be able to listen in another port to talk the memcached protocol, but this is not an high priority feature for now.
What I think people should do is to abstract the interaction with the DB in their code. So that it's just a matter of writing adapters to support new KV stores, and this adapters can take advantage of peculiarities in specific stores.
For instance if using Redis one can use Redis Sets to take the list of friends. When using something different will serialize data as JSON, and so forth.
(id) addBookmark(title,url,taglist)
(bookmark) getBookmark(id)
(array) searchBookmarksByTag(taglist)
If it's at very low level like Db.get(), DB.set(), ... is still useful if the application just using a strict common subset of features (get/set/exists/expire/incr).
I think if people want a standard API, it's going to be the memcached API.