Runners and running ads at today's Boston Marathon

As I write this, the Boston Marathon is in full swing, and the crowds are cheering, as runners from around the world compete in the nation's oldest annual marathon. But a few people in the crowd are shouting, clapping and whistling louder than ever: corporate sponsors.

Hard as it may be to believe, until today, the Boston Marathon hasn't allowed advertising anywhere near their race. Not visible advertising, that is. They've had corporate sponsorship for some time, but it was always quiet and dignified. It still is.

Today, the only change is that there will be visible ads at the start and finish of the race, for the two biggest corporate sponsors: John Hancock Financial Services and Adidas AG, the German sports equipment and apparel maker. And there will be ads at the press bridge and the sides of the VIP sitting area. But will the dignified nature of corporate sponsorship last?