Facebook, Inc. reported substantial increases in revenues and profit for the first quarter, mostly from a spike in mobile advertising revenues.

The social networking company posted $2.5 billion in sales, up 72 percent from the first quarter in 2013. Its $642 million net income (25 cents per share) was 193% better than the on-year total of $219 million. Income from operations was $1.08 billion, up 188% compared to $373 million in the first quarter of 2013.

"It's been a busy quarter and a strong one," said CEO Mark Zuckerberg. He noted that Facebook "also reached new milestones as a mobile company." He revealed that "mobile accounted for 59 percent of our advertising revenue."

Advertising revenue for the quarter stood at $2.27 billion, an 82 percent increase on-year. Of this total, mobile advertising accounted for 59 percent or $1.34 billion. That's larger than the fourth quarter 2013 total, the first time mobile accounted for more than half of ad revenue, at 53 percent.

Facebook held a 6 percent share of worldwide digital ad revenues in 2013. Research firm eMarketer expects Facebook's share to grow to nearly 7 percent this year. On the other hand, rival Google took 32 percent of worldwide digital ad spending in 2013.

Facebook took nearly 15 percent of worldwide ad revenue and is expected to take 22 percent in 2014. In comparison, Google's share was 49 percent last year and is expected to drop to about 47 percent by the end of this year.

Analysts said Zuckerberg has been pushing aggressively to earn more money from ads that appear on smartphones and tablets. This strategy appears to be paying off. Mobile ads helped Facebook pass Yahoo last year to become the No. 2 seller of online advertising in the US after Google. The worldwide advertising business is worth some $600 billion a year.