LinkedIn is a social networking website for people in professional occupations. Founded in December 2002 and launched on May 5, 2003, it is mainly used for professional networking. As of June 2012, LinkedIn reports more than 175 million registered users in more than 200 countries and territories.

Moodle is a Course Management System (CMS), also known as a Learning Management System (LMS) or a Virtual Learning Environment (VLE). It is a Free web application that educators can use to create effective online learning sites.
Mahara is a fully featured web application to build your electronic portfolio. You can create blogs, upload files, embed third-party resources from the web and collaborate with other users in groups.