Portlets are special servlet-like objects defined by the JSR-168 standard, and updated by JSR-268. They run in a portlet container.
Portlet websites are frequently used as "dashboards". SInce the container can display pages with multiple portlets on them, each portlet behaving as a separate web application, it makes it convenient to work with multiple apps at once. For example, you might have a stock ticker portlet, a weather portlet, maybe a portlet connecting to your broker's Internet trading system. A hurricane pops up on the weather portlet, you get a quick quote on "Builders 'R Us" on the stock ticker, and buy, Mortimer, buy!
We have an entire forum devoted to portlets. Portlets can be written in JSF, but most JSF-related portlet questions get better answers in the portlets forum.
An IDE is no substitute for an Intelligent Developer.