Info-Scape regularly uses a nuber of different open source packages. Here are some we especially like:

JBOSS

An industrial strength J2EEcontainer with advanced features like clusters, JMX management and integrated AOP which allows you to modify even vendor applications that run in this environment.

Jetty

A Java servlet container and web server, it has been integrated into commercial products from companies like IBM and Sterling Commerce. It is fast, small and can be used as part of a JBOSS deployment as well.

mySQL

A robust database engine that supports most of the really necessary features for eCommerce applications. It is an example of "commercial" open source. While it may cost money for your application, it still delivers the benefits of open source.

Note: this page is being revised...