I ran across the article on the BBC site and found it interesting. Bottom line, Google scientists were surprised to learn that the effects of high activity levels and high temperatures are not always as bad as traditionally thought.
http://news.bbc.co.uk/2/hi/technology/6376021.stm
Here, too, is a link to the published the technical paper.
http://209.85.163.132/papers/disk_failures.pdf