Being lazy has its benefits

Futures make for an interesting 'batch' RPC API - queue up a bunch of RPC calls by returning Futures instead of values, and when one is forced send them all across the wire.

This is a great way to add batch functionality to an API that didn't have it originally. Need to frob a set of zibs? store the futures of the zib frobbings in a new set, and then force them. (wow, bad faux verbs and nouns)