A portfolio concept could be implmented in the CMS a number of ways but the Portfolio Manager is a tool dedicated to this task. Items in the portfoilo are organized in categories and displayed a category at a time.
The portfolio system is different than other tools in that it only links to URLs as you may actually showcase your portfolio on pages scattered throughout your site or even the Internet. Portfolio items also support "Tags" so that you can assist viewers in finding exactly the kind of work they are looking for.