what is community builder in Joomla?

Community Builder (CB) is an extremely flexible and robust social networking solution for Joomla. CB has a huge user base, a long history and a great future.

Social websites go far beyond Facebook look-a-likes and CB has literally hundreds of built-in features and can be extended with extra (free or commercial) add-ons from the CB Team and other parties that will help you realize your very own - tailored to your specific needs - social networking website.