Facebook CEO Mark Zuckerberg. Image source: Facebook.

On the back of yet another expectation-crushing quarter, Facebook (META 2.48%) stock wrapped up the week 2.4% higher, bringing the stock's year-to-date gain to 18.4%.

Who would have guessed when Facebook stock went public in May 2012 at $38 a share that the stock would be trading at $124 just over four years later? After all, the stock's $100 billion market capitalization when it went public was criticized by many as overvalued. But between its $38 share price and its $124 price today, Facebook has posted lots of quarters of huge growth -- quarters like the second quarter it announced this week.

Once again, the social network didn't disappoint when it reported quarterly results on Wednesday.

Here's a closer look at the figures from Q2 that helped convince investors the stock was still worth its price-to-earnings ratio of 76 times earnings.

Revenue increased 59%

As usual, Facebook's second-quarter revenue came in well ahead of analyst estimates. The company reported revenue of $6.44 billion, obliterating analysts' consensus estimate for revenue of $6.02 billion. Further, Facebook's year-over-year revenue growth for the quarter actually accelerated compared to growth in the prior quarter. In the first quarter of 2016, Facebook's year-over-year revenue growth rate was 52%.

Operating margin jumped from 31% to 43%

Going into 2016, Facebook's CFO, David Wehner, warned investors that Facebook's operating expenses would increase sharply during the year as Facebook makes significant investments. The warning may have prompted some investors to prepare for expenses to increase faster than revenue -- a trend that would negatively impact the company's operating margins. Wehner was right. Operating expenses did increase rapidly. Indeed, in the company's most recent quarter, GAAP and non-GAAP combined costs and expenses increased 33% and 47%, respectively. But revenue increased even faster. As a result, between the second quarter of last year and the second quarter of this year, Facebook's GAAP and non-GAAP operating margin increased from 31% to 43% and 55% to 58%, respectively.

Net income soared 186%

With Facebook's revenue soaring faster than its expenses, the social network's earnings benefited from operating leverage. Net income soared 186% to more than $2 billion, and non-GAAP EPS jumped 94%.

Rising profits were similarly evident in the company's closely watched non-GAAP EPS metric. As a result of Facebook's faster-than-expected revenue growth, the social network was able to handily beat the consensus analyst estimate for non-GAAP EPS. Facebook reported non-GAAP EPS of $0.94 -- above analyst estimates for $0.82.

1.13 billion people use Facebook. Every. Single. Day.

Facebook's size certainly isn't slowing it down. Unlike Twitter (TWTR), which revealed earlier this week it was still struggling with slow user growth, Facebook's much larger user base is still growing rapidly -- despite the fact that about one in seven people already use the platform every day.

Chart source: Facebook.

In Q2, Facebook's monthly active users hit 1.71 billion -- up 15% year over year and up 3.5% sequentially. For comparison, Twitter's 313 million monthly active users were up just 3% year over year and 1% sequentially. What about daily active users? Facebook's daily active users hit 1.13 billion -- up 16.5% year over year and 3.5% sequentially. Twitter doesn't report daily active users but said they increased during the quarter.

Facebook's ability to continue to increase its daily active user count as rapidly as it has is astounding. This trend is particularly impressive because its daily active users have generally increased at a faster rate than its monthly active users, meaning Facebook's engagement rate, or the percentage of total monthly active users using the platform every day, is increasing. In Q2, the company's engagement rate was 66% -- up from 65% in the same quarter last year and 63% in the same quarter two years ago.

It's fair to say Facebook had a very good quarter. While I'm not a shareholder, I'll forgive the stock's pricey valuation for now. If I owned shares, I wouldn't be selling.