This week's book giveaway is in the OCAJP forum. We're giving away four copies of Programmer's Guide to Java SE 8 Oracle Certified Associate (OCA) and have Khalid A Mughal & Rolf W Rasmussen on-line! See this thread for details.
Suppose you have a requirement to allow individual users create their own look and feel. Change screen and move things around the screen.
JSF allows a lot of component manipulation in the managed bean. So you could put logic in to check a user and then disable or hide components. But what about giving each users their own .CSS? Or changing layout?