Making it's rounds across the mediasphere over the past couple days is a piece on how the originally predicted values of power use in the datacenter are contradictory to the actual output. That's a good thing. As more and more companies look to centralize data storage, apps, and operations to "the cloud", efficiency of the datacenter is the key factor. Why replace a power-hungry model with another power-hungry model?
Key findings from the new study are as follows:

Assuming that the midpoint between the Upper and Lower bound cases accurately reflects the history, electricity used by data centers worldwide increased by about 56% from 2005 to 2010 instead of doubling (as it did from 2000 to 2005), while in the US it increased by about 36% instead of doubling.
Electricity used in global data centers in 2010 likely accounted for between 1.1% and 1.5% of total electricity use, respectively. For the US that number was between 1.7 and 2.2%.
Electricity used in US data centers in 2010 was significantly lower than predicted by the EPA's 2007 report to Congress on data centers. That result reflected this study's reduced electricity growth rates compared to earlier estimates, which were driven mainly by a lower server installed base than was earlier predicted rather than the efficiency improvements anticipated in the report to Congress.
While Google is a high profile user of computer servers, less than 1% of electricity used by data centers worldwide was attributable to that company's data center operations.

In summary, the rapid rates of growth in data center electricity use that prevailed from 2000 to 2005 slowed significantly from 2005 to 2010, yielding total electricity use by data centers in 2010 of about 1.3% of all electricity use for the world, and 2% of all electricity use for the US.
Reports like these help to show the industry how software like 1E's NightWatchman Server Edition has contributed to these results and how continued use will make the datacenter as efficient as possible, driving these numbers down even further.
Here is some coverage in the New York Times:
https://www.nytimes.com/2011/08/01/technology/data-centers-using-less-power-than-forecast-report-says.html
And, here is Heather Clancy's piece on the research:
https://www.zdnet.com/blog/green/report-data-centers-ate-up-less-power-than-thought/18262
Download the report for yourself here (PDF): Datacenter power use
And…take a look at the most recent Server energy and efficiency report
Server energy and efficiency report