Casey Harrell

Apple said Friday it was rejoining a program to certify its products as environmentally friendly after a controversy that could have dented sales of its popular gadgets.

Activists rappelled down a Seattle office building Thursday to get Microsoft and Amazon.com to use clean energy to power datacenters running services based in the Internet "cloud."

Amazon, Apple and Twitter were graded poorly Tuesday in a Greenpeace study of technology titans' use of clean energy to power the mushrooming Internet cloud, but Facebook, Google and Yahoo! won praise.

Environmental group Greenpeace is handing out grades to consumer electronics makers for phasing out the use of hazardous substances and Apple, Sony Ericsson and Nokia are top of the class.