The recent success of social networking have made it very easy to people the possibility to open an own service online, without spend any money. Whether you need build a social networking, below is a collection of 16 downloadable open source software.

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

Mahara. Mahara is a fully featured open source electronic portfolio, weblog, resume builder and social networking system, connecting users and creating online communities. Mahara is designed to provide users with the tools to demonstrate their life-long learning, skills and development over time to selected audiences.

Mugshot. Mugshot is an open project sponsored by Red Hat. The Mugshot site lets you track what your friends are doing online across a variety of popular web sites — music, photos, blog posts, and more. We’re also exploring an idea called Online Desktop.

Vmukti. VMukti is a Unified Social Collaborative conferencing engine. Allows access through personalized, mashable web-interface. Core features:- Video conferencing, Audio conferencing, IP Telephony, Desktop sharing, Chat, Whiteboard, Presentation & More.

Appleseed. The Appleseed Project is an effort to create open source Social Networking software that is based on a distributed model. For instance, a profile on one Appleseed website could “friend” a profile on another Appleseed website, and the two profiles could interact with each other.

SPREE. Spree is an expert search engine where users ask questions to find other participating users, who are knowledgeable in that area and willing to help.

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

Broadbandmechanics. Social networking and blogging are now commodity features. PeopleAggregator brings social web features to existing software or provides a stand alone social network of your own.

Getboo. It was created more than two years ago (April 2005) for the main purpose of learning PHP and MySQL. Also, I wanted to be trained in the web environment, because since we browse the web almost daily I wanted to know how things work. My first idea was to make a bookmarking website.

Mugshot. Mugshot is an open project sponsored by Red Hat. The Mugshot site lets you track what your friends are doing online across a variety of popular web sites — music, photos, blog posts, and more. We’re also exploring an idea called Online Desktop.

Scuttle. Web-based social bookmarking system. Allows multiple users to store, share and tag their favourite links online.

Semanticscuttle. SemanticScuttle is a social bookmarking tool (based on Scuttle) experimenting new features as hierarchical tags, collaborative descriptions or OpenID authentification. More details on the wiki.

Barnraiser. AROUNDMe is a free software suite that gives you personal Internet identity AND social tools in which to collaborate.

Isocial. iSocial is a free social networking CMS software that allows you to create your own Friendster and Orkut like sites. Use bookmarks, dating and create groups with just one mouse click. Start your profitable social networking bussiness now!

Clonesumating. It’s the open source version of the code that runs CONSUMATING.COM. It features many state of the art social networking functions including user profiles, user tagging, matching and discovery based on quirky tag combinations, group activities such as weekly photo contests and blog questions, an event calendar, RSS feeds for everything, etc. It is written primarily in mod_perl.

Icecoreopen. Much of the rationale for open source software is the opportunity for talented, knowledgeable, innovative professionals to collaborate — just what ICEcore was made for — to make the software better in every way. From usability to performance to interoperability to stability to things we can only dream about . . . things you may already be doing. We facilitate this exciting collaboration through a community that we host and facilitate.

Bevolunteer. BeWelcome to the first non profit and open source based travel/hospitality network. We, as an international community, set out to develop, run and maintain, BW-Rox, the platform driving BeWelcome, aiming to bring people together in real life. We believe that a free and open approach will promote communication across social networks and helps to create better code and new innovative features.