Also from the RAB:
Radio spots + Internet ads produce create stronger impressions. RAEL research shared at RAB2007 in Dallas shows that using radio and the Internet in combo improves unaided recall more than 4-1/2 times and aided recall more than twice as much. That’s comparing consumer exposure to one radio ad and Internet ad to two Internet ads.
Can you say “integrated campaign”?
From there the only question is this: From whom will you be buying your Internet ad?