I think TV commercials have more "reliability" or trust factor...internet ads always feel like a scam...and billboards only really work for food, when your driving and you see a big mac with the words "mmmm", that makes you remember that you need to eat a big mac soon...
SXM's billboards were nice though, to the point, utilized the product recognition of colors and the iphone and just a giant "sirius XM" app logo.