Facebook's PHP overhaul, HipHop, reportedly cut CPU usage on the company's servers by around 50 percent. You don't have to be a programmer to understand that kind of result. [...] asked Kevin Tatroe, co-author of O'Reilly's Programming PHP, to weigh in on HipHop's functionality and its broader applications.

Mac starts with some basic questions - how will it help developers, how will it help businesses - and then asks for some clarification as to what the project really is and how difficult Kevin thinks it will be for companies to adopt.