Google reported spending close to US$900m in the year's first quarter in the expense category that includes data center operations. The category Google calls "Other Cost of Revenue" also includes asset amortization, content acquisition and credit-card processing charges.

The category represents about 10% of the company's total first-quarter revenue, having increased about 21% from the first quarter of 2010.

Google's total revenue for the quarter was $8.58bn, or 21% up year over year. Its net income was $2.3bn ÔÇô a 17.3% increase year over year.

The company's CFO Patrick Pichette said in a statement that the results demonstrate value of search and search ads to Google users and showed potential of display and mobile advertising. "It's clear that our past investments have been crucial to our success today--which is why we continue to invest for the long term," he added.

Google has been highly secretive about its data center infrastructure, so very little information is available about its overall footprint. The company did reveal in November 2010 that it began Phase II construction projects in South Carolina and North Carolina.

Google said it would bring the data center in Lenoir, North Carolina, and Berkeley County, South Carolina by the end on 2011. Both facilities would use the same design as the existing data centers at both sites.

In June 2010, the US Patent and Trademark Office granted Google a patent for a modular data center design that connects multiple shipping containers with IT equipment to a central "spine" that supplies power, network connectivity and cooling liquid.