Elgg is a web application for social networking. It has all the features you would expect from a social web application. It has blogging, file sharing, social bookmarking, microblogging, activity streams, groups, "friending", user profiles, and the list goes on. However, Elgg is more than just a web application. It can also be used as a development framework for creating social websites. Developers are building impressive social media sites on top of the Elgg engine through its powerful API. They are using it to add social functionality to current websites and integrating it with other popular web applications.
Elgg is open source, licensed under the GNU General Public License (GPL). You can download, install, and use it without cost. Taking advantage of its plugin architecture, there is a community of users and developers contributing plugins and themes for others to use. Open source software and an open source community are a great combination that everyone can benefit from.
Anyone can use Elgg to create a customized social networking site. Entrepreneurs are building specialized social networking sites with it. Educators are using it as an e-learning tool. Corporations are adding it to their intranets to better connect their employees. There is a wide range of applications for Elgg and with it you have complete control over your site and your data.
This book has two main objectives: help you understand what functionality Elgg provides and explain how you can customize it to make it do exactly what you want. It is not a manual for administering an active Elgg-based site, nor is it a manual for users of Elgg sites. This book is all about using and customizing Elgg to build a