Setting up a project networking site

Updating stakeholders or team members on the status of a project is an important task for a PM. I have seen numerous PMs adding a recurring task in there project plan (MS project of course) on sending weekly emails or reports to the relevant team members. Thinking of this, the age we are living in is of collaboration, with every hooked to Facebook, Twitter and other networking sites. So why don't we have a collaboration/networking/wiki for our projects? Their are numerous tools on the Internet like wordpress or Google Sites that let you set up collaboration sites in a Giffy by which team members can keep track on anouncements, project calendar, events and other goofy things that are happening.