awareNet is a suite of social networking software for schools, designed to create a safe environment where student communities at schools across the globe can interact. It is written in PHP - based on the Kapenta framework - and runs on the LAMP stack. Local awareNet installations at schools will be joined together as a peer-to-peer network, using scarce bandwidth only for messaging and synchronization of content.

EngineY is a social network and CMS framework implemented in Ruby on Rails that is easy to customize and deploy as your own powerful and feature packed social media or CMS site. Empower users with their own blogs. Enhance collaboration with forums, groups and events. Let your users post Twitter-like status messages. Track all the activity on your site with a live activity stream. Build a custom client to access all of your site's data using EngineY's RESTful API.

The community builder script we provide - Etano - was built entirely based on requests from customers of our previous dating package (Dating Site Builder). Almost every feature ever requested was built into Etano to help you build a better site for your community members. You can use Etano to start up a dating site, a social networking site, a classifieds site or any other type of site involving groups of people, companies, products.

Twig is a Twitter clone. Almost. Currently in alpha stage. This is an experiment to try the cool Google App Engine and a little Python.

I suggest you see the screenshots first, then try the online demo. kPlaylist is a free PHP system that makes your music collection available via the Internet. kPlaylist is a music database that you manage via the web. With kPlaylist you can stream your music (ogg, mp3, wav, wma, etc.), you can upload, make playlists, share, search, download and a lot more.

Gelato CMS  is a open source Tumblr clone which has the same features as Tumblr. You can easily download and install Gelato CMS on your own web servers and start tumbling. Gelato also supports themes and plugins.

sabros.us is a system to organize the bookmarks added to your web. Same as de.icio.us, you can manage your bookmars, but with sabros.us you can do it in your own web page. sabros.us project is 'Open Source' (you can use and change the original code freely) and runs with PHP and MySQL.

a Social Networking Script as same as Tumblr.com, allow anyone can share anything to anyone, such as: Image, Video Clip from YouTube.Com, Music track from NhacCuaTui.Com, Flash,... and more , friend connect to get anything from your friends on LoanTin.Com. Loantiner is an open source project which developed by KNV Group - Vietnam, started in 10/2009. We shared this source code to help students of IT, new programmers,.... in order to learn and how to know to build a social networking website. Loantiner's source code was built based on .NET Framework 2.0, Database by SQL Server 2000 and used Mootools javascript Framework.

Sweetter is opensource software. Powered by Django Sweetter is an opensource modular microblogging system. Its goal is to provide a customizable communication system for communities, departments or enterprises. Sweetter is opensource software: you can use it, study it, modify it and distribute it under the Affero GPL license terms.