What technologies are used to build Yahoo sites?

Question

Is it all javascript client side and server side? I know they use a lot of YUI but is that what powers their front end? What about the back-end?

Answer 1

Last I heard they used FreeBSD with Apache, see here, not sure now what they are using, I could gauge a guess that it's still Apache, perhaps the AMP stack (Apache, MySql, Php)?

Edit: Also see here to read the blog entry that they use their own custom system YQL (Yahoo Query Language and Hadoop) for their cloud computing system.