by: Ilya Vedrashko
You might have already seen Clay Shirky's now famous speech about cognitive surplus given at Web2Expo and the dramatic comparison of the time spent watching TV (200B hours a year in the US) and building Wikipedia (100M hours total).
He mentioned another number I thought was interesting: "In the US, we spend 100 million hours a weekend watching just the ads" (fast-forward to 5:52, or read the transcript). The order of magnitude seems right but I can't figure out how he arrived at his estimate. Here are the inputs I'm working with.