There is an interesting article on Olio toolkit on High Scalability site that brings up a very good point about evaluating different technologies before deciding which one is most suitable for your application needs. There is a common trend that I see among new gen startups, where PHP developers starting their new companies and using Ruby on Rails over PHP due to its performance, ease of use, and rich functionality set. With every application there are different factors that need to be accounted for. How do you select technology, database, underlying deployment environment, and how do you know that it is indeed the stack you can reliably deploy your application on? Olio allows you to validate these questions. Interestingly Apache's Olio evolved from Sun's Web2.0kit, and now there are three implementation of it in Java, Ruby, and PHP. When it comes to optimized Web2.0 stack, the OpenSolaris community use the Webstack which embraces multitude of components such as Apache, MySQL, PHP, Drupal, and allows developers to leverage performant components of a traditionla Web 2.0 applications on OpenSolaris. You can learn more about Webstack and become a community contributor.