Web applications which are opensource

Question

I am interested in web applications. So I came across Reddit and Jaiku for which the code is available in the public domain. Do you know any other such sites for which the source code is available?

It will be useful for interested people to learn about the web applications from these websites.

Answer 1

For Blogs there is good opensource project: BlogEngine

For Content Management Systems

1. DotNetNuke
2. Joomla

Answer 2

There is a good survey tool called LimeSurvey: http://www.limesurvey.org/

Answer 3

Sourceforge would be a great place to start looking as it hosts thousands of open source projects including many web based ones. Freshmeat is another fantastic resource.

What types of web applications did you have in mind?