Facebook PHP HipHop

The main article about this technology available for the moment is on facebook http://developers.facebook.com/news.php?blog=1&story=358 . Feature is that php code translates into the C++ source codes, then it compiles into byte code. In between it is used different kinds of optimizers.
I find this very interesting, as this technology combines speed of development in PHP and speed of processing in C++ compiled. And also it is very important that they make it transparent for PHP developers, so that they don’t need to transform code to the C++ code and then compile it. It is done according to the article quite automatically by using HPHPi interpreter.
I think in few days we’ll be able to check it ourself when http://github.com/facebook/hiphop-php/wikis and http://groups.google.com/group/hiphop-php-dev will be available.
Such kind of technologies where expected to appear due to high load on some services. Instead of adding new servers into clusters it is really a possibility for slow languages use something like this.