Boonex Dolphin is an open-source, downloadable, scalable, customizable, full-featured and independent for building social networks, dating sites and niche communities. Dolphin is the only “all-in-one” bundle of PHP community scripts, Flash plugins, Adobe AIR and Mobile apps that provide full control, freedom and flexibility. Launch your site, customize it and watch it grow!
Elgg is an award-winning social networking engine, delivering the building blocks that enable businesses, schools, universities and associations to create their own fully-featured social networks and applications.
Elgg is open source social networking software that provides individuals and organizations with the components needed to create an online social environment and offers blogging, microblogging, file sharing, networking, groups and a number of other features.
SocialEngine is a PHP-based white-label social networking service platform, that provides features similar to a social network on a user’s website. Main features include administration of small-to-mid scale social networks, complete customization abilities, unencrypted code, multilingual capability, and modular plugin/widget compatibility. There is a range of templates and add-ons available to extend the basic features already included in the SocialEngine core.