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.