Noosfero is a Web platform for social networks. Besides the regular social network features (such as friends and communities), Noosfero offers a full-featured CMS, making every user or community profile a complete Web site with several types of content (including text, image gallery, and file uploads), RSS feeds, agenda, the possibility to set custom themes, and other features. It is also possible to run several independent social networks within the same Noosfero installation.
Modelbook is a social networking platform that features most mainstream social networking features: Paypal subscriptions, friends request/approval, shout-outs, wall castings/events, a forum, profile approval/private profiles, image galleries, MP3 upload, Zip code radius search, Facebook-style chat, and more.
Pipinstrasse is software to implement a social network for groups, families, or neighborhoods. It features user accounts and profile pages, photo galleries with automatic scaling, a pinboard, private messages, chat, invitations to email addresses, guest access to selected photo galleries, and a start page with "wall" and "like" buttons. Typical use cases are private Web sites for neighborhoods, families, or clubs, where members want to communicate, but no public facing Web site is needed. Use generally is for members only. New users can register through a Web form, but need to be activated by an administrator. However, there is a guest facility, which gives invited guests access to selected photo galleries. Graphic design is done through themes, which are separated in their own directories.