This looks awesome. Transparent, coherent caching based on a very fast backend (Memcache). The main point to remember is coherence: it automatically takes care of data mutation for you, unlike classical Memcache. This is not trivial to implement (I tried).

I wonder (I hope) if this could erase the perceived Rails "can't scale" problem from the public discourse.

Also, does anybody know about a PHP equivalent ? Yeah, I'm doing PHP at my day job and I badly need it.

upmodded for best plugin name ever

But does it work with Merb?

It could be extended to work with DataMapper in a straightforward way.

If you use ActiveRecord, it's easy enough to hack, but what's the point of an AR-based Merb app?