Being a privacy nightmare, I can see how this data can be quite useful for advertisers simply by sniffing DNS traffic: * What sites do they visit? * How long

Being a privacy nightmare, I can see how this data can be quite useful for advertisers simply by sniffing DNS traffic: * What sites do they visit? * How long do they spend on each site? * What apps do they use? (apps make http requests, after all) * How long do they spend on these apps (providing it's making consistent http requests) * What devices are they using to access these sites/apps? Kind of like Neilson ratings but for the web.