Over 100 million saw it. But they only saw it once. Budweiser purchased time during the Super Bowl the year after 9/11.
It was a tribute that featured the famous Budweiser Clydesdales. Much effort had to be made to make the video. WGN reports that Anheuser-Busch had to get the permission from politicians and the city of New York to film the scenes over the Brooklyn Bridge. It was a big deal to get access to that airspace for obvious reasons.