How do I enable the syndication tab in Plone 3.0?
By default, outgoing syndication is enabled in Plone 3.0. However, you must explicitly configure Plone to display the syndication tab.
In the ZMI, go to portal_actions / object / syndication and then tick the Visible checkbox and click on the Save Changes button.
Now when you're on a folder in Plone, the syndication tab will show up as you expect.