Imagine you are an advertiser, you want to place your banners on the most popular website, and you want to know how much to pay.



Globally, the leading site is Google, which has the most "page views". Or is it Microsoft, whose various sites have, in the jargon, the most "time spent"?

Or should you go by unique users, duration, hits, click-through, impressions, queries, sessions, streams, or engagement?

Whether or not there is truth in advertising, there is certainly none for online advertisers, at least none that is immediately obvious and simple.

The web produces data as "a fire-hose shoots water", and that working out what those data mean is rather like "putting a straw into the fire hose to take a sip". Get the angle even slightly wrong, and you are blown away.

Read the full article at the Economist