Whoops I already have a Rojo account
After whingeing :-) about not getting an invitation to Rojo, Marc pointed out that I already do have a Rojo account that he invited me to previously! D'oh! Mea culpa, etc.
I don't see how Rojo is better than NetNewsWire (unless you can convince your peers to join and share what they are paying attention to which I can't but maybe Steve has), but perhaps Steve can clarify that in a future post.