Portlets are little modules that allow extra (often dynamic) information to be added to any page. For instance, rss files to be displayed, several rss files to be collected together and displayed, a calendar, a box of static material, etc. They may be added to the right hand side of any page. The portlets shown on the right side of the home page will be inherited through all folders and pages unless this inheritance is blocked. Below is an example of a second level page with right-hand portlets added:
When portlets are being inherited, you can still add extra portlets to the page. Inheriting portlets is an 'all or nothing' function - if you wanted only one of an inherited group, you will need to block them all and manually add back the one you want to keep.
When adding portlets to your home page, the use of portlets on the right side of the page is that same for all pages, only on the home page can you also add a variety of portlets to the content area.