Description: Mailman is an open source mailing list management system. It helps manage email discussion and announcement lists, allowing users to subscribe and unsubscribe, and helping admins moderate and post to the lists.
Type: software
Pricing: Free
Description: Stack Overflow is a popular question and answer site for programmers. Users can ask coding questions and receive answers from a community of developers. The site has a reputation system to rate helpful responses.
Type: software
Pricing: Subscription