Since apparently, I was the first person to ever publicly spill the beans on HipHop, I need to do penance by clarifying what HipHop is and what it means for PHP.
For those of you who don’t have time to read the rest, here is what HipHop for PHP is:

• HipHop is a PHP-to-C++ cross-compiler. What this means is it takes PHP code and translates it into C++ code for further compiling. It is not another language. It is not a just-in-time compiler (JIT).. Read more..

No, I’m not talking about a break-dance move that will magically give you extra PHP performance. I’m referring, rather, to a new open source project announced by Facebook. HipHop is a “source code transformer” designed to reduce CPU and memory usage by transforming your PHP code into C++ code. Read more..