"RPS" (Revenue Per Mille or Thousand Sessions) and "RPM" (Revenue Per Mille or Thousand Pageviews) are two key metrics in advertising that offer different perspectives on your advertising performance.
In essence, RPS provides a macro view of revenue performance per thousand sessions, while RPM offers a micro view of revenue performance per thousand pageviews. The choice between RPS and RPM depends on your specific optimization goals and the level of detail you require for evaluating your advertising performance. In some cases, RPS and RPM may be nearly identical, particularly if the pageview-to-session ratio is close to one for a given website.