Please let me know through email or a comment if you know of any other great social bookmarking, network, filesharing or search applications,
and I'll be glad to post them. Also special thanks to all of the folks who produced all of this great free software.



Social Bookmarking


Akarru: Social BookMarking Engine

Akarru is a social bookmarking engine, is used to build social bookmarkings sites, like http://www.blogmemes.com. Users posts links and promote links to front page using voting system.



Bookmark4U

Bookmark4U is an web-server application, which is based on Apache + PHP + MySQL. Bookmark4U is intended to provide a comfortable bookmarking environment for users.



CommunityNews

CommunityNews uses social bookmarking and bayesian techinques to provide periodic postings to blogs. Users can vote for or against RSS sources ti increase the chances that the source is used again. Spam filtering (bayesian) is provided by spam bayes.



ContARTE

ontARTE is a social bookmarking multiuser engine, is used to build social bookmarkings sites, like http://www.contarte.info.



GetBoo

Web 2.0 bookmarking system, both social (with tags) and private (with folders). Import and export your bookmarks from Firefox, IE, Mozilla, Netscape. Admin management section, translations, groups, bookmarklets, Firefox extension, RSS feeds, and more!



Laicos - Social Bookmarking in ASP.Net

Laicos or social backwards is a social bookmarking website development application. Use this project to create a Digg style clone. In asp.net and MySQL environment.



Scuttle: Open source social bookmarking

Scuttle is a free open source software for creating social bookmarking sites like del.icio.us. You can create a social bookmarking site in minutes using scuttle for your personal or for community use. Scuttle supports most of the del.icio.us API, so you can modify the del.icio.us tools to work with scuttle. Import your existing bookmarks from browsers or from del.icio.us. Scuttle has several AJAX features and it generates an RSS feeds.



Taggly

Taggly is an online social bookmarking software written with usability and scalability in mind.



Unalog

Open source bookmarking software written in the Python programming. You can get an account and add your own links, and create and join groups. If you get an account, or create a group, either one can be made private, so nobody but you (if a private account) or your fellow group members (if a private group) can see your links.



Social Filesharing


Asmaan

Asmaan is a multi-client chat software with built-in social networking and bitorrent filesharing with search, encryption and partial anonymity.



Bittorrent-2

Define 2nd generation Bittorrent protocol with social networking, recommendation, tag-based navigation, distributed moderation, and real-time streaming. Remove .torrent, tracker, and website from architecture. Create reference implement. with ABC project.



Torrent Swapper

Lightweight python based 4th. generation bittorrent client with social networking, recommendation, tag-based navigation, moderation, and real-time streaming.



Tribler

Define 4th generation file sharing system with social networking, recommendation, tag-based navigation, moderation, and real-time streaming. Remove .torrent, tracker, and website from architecture. Create reference implement. with Bittorrent ABC project.



Social Networking


Affelio

Affelio is open-source social networking software / architecture. It has following features: (1)distributed architecture (2)Internet-wide scalability, (3)Extensivity with opened Affelio API for developers, and (4)high custamizability with skins/templates.



AstroSPACES

AstroSPACES is the world's first open source social networking solution. Coded from scratch, it is highly efficient and very easy to use.



blogBOX

blogBOX is a free and open source social networking system written in PHP. Future versions will be written i Python/Django.



Elgg

Elgg is an open source social networking platform developed for LAMP (Linux, Apache, MySQL, PHP) which encompasses weblogging, file storage, RSS aggregation, personal profiles, FOAF functionality and more.



FlightFeather: Social Networking Platform

FlightFeather's goal is "social networking for everyone". This means that anyone should have a chance to run a popular social networking site -- on minimal hardware, and without wasting bandwidth.



FriendPortal - An Open Source Friendster

An open-source, Friendster-like social networking portal and news site written in PHP. Post and read news plus browse through contacts like you would in Friendster, Orkut, Tribe.net or Ringo with the knowledge that your personal information is safe.



Geek Grep

GeekGrep is a Django based social-networking system designed to get geeks connected with each other. The main feature is a database of geek codes and the ability to search them. See our project web site for a design template of the future site.



Hiitch: The Social Networking Platform

Hiitch is a secure and advanced desktop social networking platform. It allows you to build a focused and private network of communities for your family, friends, company and etc. It gives you total control and freedom for your social networking needs.



iSocial: Social Networking CMS

Social Networking script written in PHP and MySQL. Designed for every kind of communities - can easily create their own social networking website for free with no ads.



Jahnet

The JahNet framework is a Open Source social networking and asset management CMS that is focused on helping digital artists collaborate on a global scale. JahNet allows you to securely share your ideas, images and projects with users around the world



Manusya

The Manusya application is an opensource social networking application being built on mod_perl, Perl Template Toolkit, Postgresql, Apache and Linux. The manusya_web_core packages are required for the front-end.



Melt: Online Social Networking Software

Melt is "social software" intended for NGOs to build online social networks, where people can announce events, create groups to organise those events, and add resources (files and web links) to support organisers. Everything can be tagged and linked.



OpenPNE

OpenPNE is a Social Networking Service Engine written in PHP. It has many features(friend control,friend invitation,diary,blog feeds,message box,etc).



Openpublic

OpenPublic is an interest group social networking and collaboration platform. It provides a solution for mutual interest and special interest groups and membership based organizations wishing to create a knowledge network around their interests.



OpenVZ

OpenVZ is an open source social networking system.



Phpizabi

PHPizabi is one of the most powerful social networking platforms on the planet.



PHP-Spacester

PHP-Spacester is a social networking script such as Myspace and friendster. It is a fork of astrospaces. It will feature the XDNS system (Xotmid Distributed Network System) which is a leaf-hub connection thus allowing anyone to run a leaf and connect to.



Pihook: Social Networking System

Open source social networking system.



Snoss

Social Networking Open Source Software, an open source social networking framework, written in PHP, Javascript and MySQL with an AJAX UI.



Tag Me

Tag Me is a social networking application that allows people to send information about themselves via bluetooth or by mobile web browser you create an online wml website and create a url barcode that holds the link to your online profile.



The Apple Orchard

The Apple Orchard is a multi-user, open source social networking web application with the ability for users to upload photos and videos, write a blog, have comments, personalise their page layout and appearance and sort multimedia by tags.



The Appleseed Project

Appleseed is (augmented) social networking software, ie Friendster, only distributed. Sites running Appleseed will interoperate, and form the 'Appleseed Social Network.' Development is focused on privacy and security, as well as ease of configuration.



Virtual Learning Commons

The Virtual Learning Commons software combines a web based content management system, academic tools and social networking to create a website. Can be used by groups to create web based content within an integrated social networking environment.



WorldSpace

WorldSpace is a user-extensible shared virtual environment, aimed at being a next-generation social networking system.



Yogurt: Social Network

This is a Social Network module for xoops CMS. You have seen Facebook, Orkut, Myspace , try Yogurt for Xoops!



Social Search


Facelift

Facelift is a visualization and analysis software for online social networking services. It displays a given community as a node-link diagram and provides several search / filtering functions as well as cluster analysis features.



Social Semantic Search and Browsing

S3B - Social Semantic Search and Browsing - is a middleware that delivers a set of search and browsing components that can be used in J2EE web applications to deliver user-oriented features based on semantic descriptions and social networking