A friend* of mine tipped me of on a quite interesting study conducted by a Belgian economist. Daam Van Reeth studied how a number of different variables - like the parcourse, doping news, uncertainty about the outcome, and patriotism - influence the TV audience during Tour de France. He only use data from Flemish television, but since Podium Cafe is the site where people dream of Belgium, we might learn something from the study anyway.
Now, there are not a lot of surprises here. Belgians love high mountain stages, and even more so if it's mountain top finish. The 10 most viewed stages between 1997 and 2010 are all high mountain stages, and 8 of them finish on a mountain. Number 1 is the Tourmalet stage in 2010, and number 2 is the Morzine stage the same year. But that is only true for average audience, when it comes to peak audience, two Paris stages is 1st and 2nd. Tourmalet 2010 is 3rd, and Mont Ventoux 2009 is 4th.
On the other hand, the stages that interest the Belgians the least are time trials and flat stages during the first week (bunch of wackos...). The prologue in Strasbourg in 2005 is the number 296, both for average audience and peak audience. Compared to the baseline, the audience is more than 34,000 fewer during a individual time trial, and more than twice as many stay away during a team time trial.
Even more obvious is that a close race is positive, same goes for Belgian success (with Van Den Broeck adding even more viewers in 2010). Van Reeth also introduces a "Boonen-dummy" (funny on so many levels) to see how if Boonen's absence in 2008 lowered audience that year. It did, at least the average audience was almost 35,000 fewer because of his ban. The result for peak audience is not statistically significant, but indicates a rather curious positive effect.
Apparently, Belgians love when the race goes through Belgium. Well, at least when the race visits Flandern, the audience goes up a lot during those stages. The Walloon stages is far behind in popularity, and barely significant.
To finish this post, two interesting tidbits. First of all, Armstrong's comeback raised the number of viewers. Not by a lot on average, but the number for peak audience is not far behind the same number for Belgian success. Secondly, doping news doesn't make much of a difference, the Belgians watch cycling anyway.
*He said it was important research. At the same time, his interest in sports is rather limited. It's possible that he was sarcastic.