Google announced today that they earned nearly $10 billion in revenue in the third quarter of this year, resulting in a 33 percent year on year increase for the search giant. CEO Larry Page also said that Google+ has surpassed the 40 million user mark.

Google reported revenues of $9.72 billion for the quarter ending September 30, 2011. This figure doesn’t represent traffic acquisition costs which totaled $2.21 billion. GAAP operating income was calculated at $3.06 billion, or 31 percent of overall revenue. In comparison, the company spent $2.55 billion in the same quarter last year.

More specifically, Google-owned websites represented 69 percent of total revenue, or $6.74 billion. Partner sites generated ad revenue through AdSense programs of $2.60 billion, or 27 percent of revenue. Interesting enough, 55 percent of total revenue came from outside of the United States.

A few weeks ago, co-founder and self-proclaimed Google+ unofficial statistician Paul Allen (no relation to the Microsoft co-founder by the same name) estimated that Google+ was slowly approaching 50 million users. At the time, his calculations determined the site had 43.3 million users. Depending on when Google gathered the 40 million user figure, Allen’s estimates could be spot-on.

It’s still too early to tell if Google+ will be a serious competitor to Facebook, the most popular social networking site in the world. At Facebook’s f8 conference last month, the company announced they had over 800 million users worldwide. Facebook CEO Mark Zuckerberg used the conference to introduce a wealth of new features to the social site including Timeline and Open Graphs.