Now when I first saw this acronym, I did wonder what REVS PER MINUTE had to do with Google Adsense! But no, wrong subject!
RPM – Page Revenue Per Thousand Impressions
In relation to Google Adsense, RPM or Page Revenue Per Thousand Impressions is a calculation based on the estimated earnings accured for every 1000 page views, queries or impressions.
Estimated Earnings / Page Viewed x 1000
Estimated Earnings: $0.10
Page Viewed: 20
Multiplying Factor: 1000
RPM Calculation = (0.10/20) x 1000
RPM = $5