PHP is a general-purpose server-side scripting language originally designed for Web development to produce dynamic Web pages.

Twig in Drupal Core

Last week it was announced that Twig will be incorporated into the next release of Drupal, version 8, due for release later in 2013. Drupal has previously used the PHPTemplate system in order to separate business logic from the presentation layer.

Migration to Twig makes Drupal theming far more secure, and potentially will make sites faster and accessible to a wider community of designers and developers.

Drupal Hosted on Google

Google App Engine (GAE) now supports PHP. This means that sites built on platforms such as Drupal or Wordpress can be hosted within the massive Google infrastructure. GAE charges by CPU usage instead of instance hours so, for sites with low traffic, hosting can be much cheaper. And if your site suddenly gets hits from lots of users, the load is spread across the Google's vast vast computing cloud so your users still get their pages served quickly.
The only current problem is that GAE is not quite an out-of-the-box solution for Drupal: there's an excellent tutorial on installing Drupal on GAE at Boombatower.