Built-in Windows 8 applications have ads

"Despite the fact that I've been using Windows 8 for the past three weeks, I somehow managed to overlook a rather stark feature in the OS: ads. No, we're not talking about ads cluttering up the desktop or login screen (thankfully), but rather ads that can be found inside of some Modern UI apps that Windows ships with. That includes Finance, Weather, Travel, News and so forth. Is it a problem? Let's tackle this from a couple of different angles." Hadn't seen them either - I don't use those applications - but this is pretty despicable.