Sez Marc at O’Reilly Radar:

It’s definitely true that “RSS” is not a helpful term to describe feeds to the world at large. Yet another acronym, spewed into the environment by the worst language polluters on the planet, the tech industry. But you know what? It’s already too late. Just like ‘http://’, RSS icons are a usability disaster that will be around for the long haul. The tools will have to route around the damage.
(Atom has a Branding Problem)