@sundaridevi : correct observations.
Similar metrics, based upon data collected by Google in various ways, are also supposed to be used for AdSense in order to optimise revenue -- but AdSense relevance is abominable most of the time - thus the low CPCs most publishers experience.
Theoretically, it makes sense to use such metrics in influencing search results as part of an algorithm prevalent in on-page-content RELEVANCE factors. However, for the time being, there seems to be a considerable gap between theory and practice.
In the meantime, of course, Google has an army of low-paid idiots manually penalising sites, or group of sites, according to their "judgment", psychological problems and their own "interpretation" of what Google has provided them as guidelines . . . .