Greenest IT Brands - Apple, HP, Microsoft

GreenFactor conducted a recent Green IT brand study.  Apple, HP, and Microsoft are the top Green brands. I was staring at these three companies trying to see a connection. What are these companies doing to make them #1 in the list?

Apple, HP, Microsoft Perceived As Greenest IT Brands

The one thing that is a connection between Apple, HP, and Microsoft is these companies are my employment resume. In sequence, I worked 5 years for HP, 7 years for Apple, and 14 years for Microsoft. How's that for a coincidence?