Facebook lets you make friend lists, but they're static unless you manually update them. To make things easier, I implemented another tab under the section for managing your friends called "Smart Lists." These could be automatically created and automatically updated, based on people's profile information.
To bring up the coworker example again, if people you work with have the company listed in their profile information, Facebook will be able to discern that they're your current coworkers, and it could keep this list updated so you don't have to actually manage this list on your own. In other words, you wouldn't have to remember to add a new coworker to a particular coworkers smart list -- Facebook would do that for you.
NEXT: Jason Brush