This document provides information on several social networking and collaboration platforms: - Elgg is an open source social networking platform that can be customized with plugins. - Google Apps is Google's software as a service offering that provides customizable versions of Google products like Gmail and Docs. - Open Atrium is an intranet and team portal based on Drupal that includes features like blogs, wikis, and calendars. - PBworks is a paid service and the largest provider of hosted collaboration solutions for business and education. - Microsoft SharePoint is a proprietary software platform for collaboration, publishing, and portals.