We're rate limiting how many items/users gets handed out. Because Posterous is very fragile, and we're blowing away their front end caches - which they rely on

We're rate limiting how many items/users gets handed out. Because Posterous is very fragile, and we're blowing away their front end caches - which they rely on heavily. Because of this, we practically hit the back end every time (as well as other users of Posterous, because we blow the cache away) - which makes Posterous very slow. We've ran a few hundered more threads earlier, successfully making Posterous completely unavailable unfortunally.