I recall that one of the early metrics at Google was actually how short a time the user spent at their site. The idea (absolutely correct, IMO) was that the sh

I recall that one of the early metrics at Google was actually how short a time the user spent at their site. The idea (absolutely correct, IMO) was that the shorter the visit, the more successful the search was. I.e., if they provide exactly the desired result at the top of the list, the user would promptly click off to their desired destination, whereas if they gave poor results, there would be many more search actions. However, they have long since strayed away from such sound reasoning.