Google earned just shy of US$10 billion in the three months to September 30, 2011, the company has announced.

The figure represents a 33% increase compared with the same period of 2010. Operating income was US$3.06 billion, compared with US$2.55 billion in the third quarter of 2010.

The other revelation from the announcement is that the company's fledgling social network, Google+, has now passed the 40 million user mark.

The network was opened up to the public late last month, and although the user base isn't as high as some have estimated, it still represents a solid foundation.

Google's CEO, Larry Page, is understandably pleased with the results.

"We had a great quarter,” Page says in a statement.

"People are flocking into Google+ at an incredible rate and we are just getting started.

Go here for the full figures.