"And if we’re going to use a persistent store, why add a layer of complexity (and cost) to the architecture when Web 2.0 has shown us it is not only viable but

"And if we’re going to use a persistent store, why add a layer of complexity (and cost) to the architecture when Web 2.0 has shown us it is not only viable but inherently more scalable to go directly to that source?" Well, there's a reason everyone and their mom is using memcached: Going directly to the db does not always scale that well ..