Clearly there is some reason to do this. I mean, Google does it, and they employ some of the most brilliant people on the planet. Showing people their website

Clearly there is some reason to do this. I mean, Google does it, and they employ some of the most brilliant people on the planet. Showing people their website in the wrong language is clearly losing them money, so minimizing that is a very direct way to increase profits. There must be some reason they rely on IP more than on Accept-Language. They don't leave money lying around, and there's no way Google engineers aren't aware of that header. I don't know why they do it, but somehow Accept-Language must be less reliable than IP. No other explanation makes sense in this context.