Traditionally the server side of web applications has been written in PHP, Perl, Python, Java, C/C++, etc. Javascript traditionally was implemented only in web browsers, and hence Javascript programming has been almost completely focused on the client end of web application development. It's arguably better to have the same programming language on both client and server sides of web application development, maybe. Several attempts have been made to implement javascript for server side web application development. A new javascript stack, Node.JS, is getting a lot of attention.
Palm Developer Podcast Series: Episode Nine - webOS 2.0 SDK is Ben and Dion talking about Palm's latest OS release and it's rather interesting because WebOS 2.0 includes Node.JS support. Their background includes a long stint at Mozilla in Mozilla Labs where they did basic research on what web application development can be. Their focus is on HTML5 and Javascript to build the sort of applications which used to be done with Flash or Java.
The bit on Node.JS is in the first 1/3rd of the recording.
CommonJS sprung from Mozilla to pull together libraries one would need to run Javascript on the server.
Describe NodeJS as the potential to be one of the great open source communities.