* They all require two servers running (redis + a web server)
* None provides a framework for building an application.
* None provides n-way replication.
* None provides offline support.
I get that they do mean you can build a web app. The question above was why it would make sense to use couch instead of redis. The primary answer is because the database already does most of what you want (including serving the HTML to the web browser) since it speaks the same language as the eventual client.
>They all require two servers running (redis + a web server)
So? separating web service access to the datastore is simply separation of concerns and just good modular design. A redis hybrid solution is still going to be faster than Couch.
>None provides a framework for building an application.
There is lua scripting available in some of them and the application fx is generally on the client.
>None provides n-way replication.
Out-of-the-box Redis supports trivial (as many as slaves as you want) replication.
