Yahoo! used symfony to redevelop another project. This time symfony was used as part of the foundation for Yahoo! Answers. Yahoo! Answers is the largest collection of human knowledge on the Web with more than 135 million users and 515 million answers worldwide. Yahoo! Answers is the 2nd ranked education & reference site on the web and is available in 26 markets and 12 languages.

Why did Yahoo! choose symfony for another large web application project?

Philosophy

Full-stack framework for building complex web applications
Adopt best ideas from anywhere, using existing code if available (Mojavi, Prado, Rails, Django)

Design

Clean separation between Model, View, and Controller
Controller using modules and actions
Views using templates in straight PHP with helpers
Easy to reuse view modules to compose a page (Layouts, Components, Partials, Slots)

Configurability / Flexibility

Features we do not want are easily disabled
Use of factories for easy customization

Documentation / Support Community

The Definitive Guide to symfony (free online)
Excellent tutorials and example applications - Askeet
Active community with wiki, mailing lists, forums, irc channel

Once again symfony fits the requirements of an enterprise web application. Dustin Whittle of Yahoo! presented a case study on redeveloping Y! Answers. The focus was how to work with open source tools to create a complete framework (PHP, JS, CSS) for the enterprise. He used his experience redeveloping Yahoo! Answers with symfony and Yahoo! User Interface libraries as a case study. Download the presentation from slideshare.