Up until recently SharePoint was being used within an organization for internal purposes, Intranets, team sites, and file share servers. It had a somewhat difficult licensing model for public facing sites so you didn’t see as much SharePoint in the public facing world. That, however, is changing with SharePoint 2010. The licensing model is completely different and allows you to run both internal and external facing sites on the same server. Now, more than ever you will see some amazing public SharePoint sites. Here’s a good place to start http://www.topsharepoint.com/