Facebook's (META -0.52%) much-anticipated third quarter is behind it, finally. That sound you hear emanating from Facebook HQ in the Menlo Park area is a huge sigh of relief. There's no denying Facebook's mobile numbers are looking up, as are earnings and revenue.

What really stands out to me, even more than the positive Q3 results, was the manner in which CEO Mark Zuckerberg shared the news. Zuckerberg has long been maligned as the hoodie-wearing anti-CEO, and rightfully so. But a quick glance at Facebook's Q3 earnings announcement (link opens PDF) reinforces the notion I'd first alluded to in an article a few weeks ago: Facebook is growing up.

First, the particulars
Facebook revenue for Q3 jumped 32% vs. the same period a year ago, to $1.26 billion. The good -- and bad -- of Facebook's revenue results is that $1.09 billion came from advertising, a 36% increase from 2011. Personally, I'd like to see some diversification in revenue lines, but this, too, shall come. Regardless, the sales figures are a solid improvement.

The increase in revenue didn't translate to bottom-line growth, however. Earnings of $0.12 a share in Q3 were flat compared to 2011, and the culprit was higher expenses, which is not surprising considering Facebook's growth stage. The 64% increase in Facebook costs includes a 7% hit for stock-based compensation during the quarter.

The news that really shook up investors -- in a good way -- was Facebook's mobile results. Of the 1 billion monthly active users, over 600 million are mobile, a 61% increase over last year. Just as notable, Facebook generated 14% of its advertising revenue in the third quarter from mobile.

Clearly, Facebook's efforts to make the smartphone user experience more dynamic are taking hold. With the new Google (GOOGL 0.55%) Android OS messenger service, along with revamping its technology to perform better on Apple mobile products, including the latest mini iPad, Facebook's mobile efforts are paying off.

Risks remain
One quarter doesn't alleviate nearly six months of angst since the Facebook IPO, of course. The competitive landscape is still a concern. Google's social media service, Google+, is growing at an alarming rate. With over 400 million users, 100 million of which are "active," Google+ is becoming a social media force, albeit at one-tenth the scale of Facebook.

The pop in share price since the Oct. 23 earnings announcement (about 25%, so far) is great for Facebook shareholders who've stayed the course. But I submit there's even more to be excited about than Q3 results, and it's written by Zuckerberg right there at the beginning of Facebook's Q3 statement: "As proud as I am that a billion people use Facebook each month, I'm also really happy that over 600 million people now share and connect on Facebook every month using mobile devices." "So what," you ask?

Beginning Facebook's Q3 earnings announcement with mobile results wasn't an accident. Facebook is growing up. Not long ago, a I could see a subtle PR move like addressing the primary concern of Facebook shareholders from the get-go being pooh-poohed by Zuckerberg. No longer.

Facebook is slowly realizing shareholders are invested, too. Maybe I'm reading too much into the earnings announcement; but I don't think so. Facebook is growing up, and it's right there to see -- if you read between the lines.