"But will it scale?"

Doing some remedial reading on this summer's Great Twitter Scaling Kerfuffle, found a great quote from Phil at Progressive Data Solutions, in his writeup on Railsconf: "To me, this question is a "shark-attack" question. Sure, you could get attacked by a shark if you go swimming in the ocean, but you should probably worry about other things first, like rip-tides, water temperature, etc. If you ask me this question, I will usually respond with numbers. It's hard to argue with concrete numbers, and that's what the Joyent presentation did a good job with. If Twitter is getting 11,000 requests per second at peak, they need roughly 32 cores to handle the traffic. Is your app going to be getting 11,000 requests per second? How about 1000?" Nice!