I have a question...how big is the backend to this site? Its average response is about 100ms, which, to me, seems impressively fast considering the number of bulk records and the amount of concurrent traffic that such a site is getting. Besides the obvious indexing of the email field...anything special behind the curtains? Lots of machines? Something else besides a simple key lookup? Or am I just vastly overestimating how slowly a properly maintained DB will respond in such a situation?