Question about running memcached on multiple servers

I have memcached running on two boxes and memcache-client installed and am ready to integrate into my Rails app.

I see lots of references to running the memcached server daemon process on several servers. This implies that you would have completely different caches on each machine, correct? So you would just fire up as many cache processes as you need to cache different items in hopes of distributing the load.

There isn't any notion of some sort of distributed cache (cache that lives on multiple servers), right? That would seem to imply some sort of replication or cache server affinity.

Right... from the memcache page...