• by Gavin O'Malley  @mp_gavin, April 22, 2015

Despite just missing analysts' revenue expectations, Facebook posted healthy first-quarter earnings and engagement numbers, on Wednesday.

It was a “good quarter and good start to the year,” Facebook CEO Mark Zuckerberg told analysts on a conference call.

Revenue for the first quarter totaled $3.54 billion -- an increase of 42% year-over-year -- while ad revenue was up 46% year-over-year to $3.32 billion.

Now a mobile-first company, Facebook says mobile ad revenue represented about 73% of total ad revenue for the first quarter -- up from about 59% of ad revenue in the first quarter of last year.

Daily active users (DAUs) were 936 million on average in March -- an increase of 17% year-over-year. Mobile DAUs were 798 million on average in March, which represented an increase of 31% year-over-year.

Monthly active users (MAUs) were 1.44 billion as of March 31 -- an increase of 13% year-over-year -- while mobile MAUs were 1.25 billion as of March 31, which represented an increase of 24% year-over-year.

Analysts said growth in usership and engagement were critical to Facebook’s continued success. “I can say that Facebook has proven why it remains so strong in this space,” Forrester analyst Erna Alfred Liousas said on Wednesday. “It continues to improve the user experience.”

For the quarter, Sheryl Sandberg, Facebook’s COO, said performance was strong across all marketer segments. This was, in large part, because Facebook is a “great platform to do creative storytelling on mobile,” along with the continued growth of video, she said.

That said, Sandberg said Facebook only takes a tiny share of brand dollars. Not even its biggest clients spend more than 5% of their budgets on the social giant, she said. As such, there’s plenty of room for growth, Sandberg said.

In particular, Instagram holds plenty of monetization potential, Zuckerberg noted. At the moment, however, Facebook’s primary goal is to increase the quality of Instagram’s user experience, he said.

Amid Instagram’s continued success, Facebook’s ability to monetize the network remains to be seen, according to Debra Aho Williamson, principal analyst at eMarketer.

“We're still waiting for indications of how much ad revenue Facebook is getting from Instagram,” Williamson said on Wednesday.

What’s more, “It will be important in coming quarters for the company to start to show how much momentum [Facebook’s] gaining in video advertising and off-Facebook ad targeting,” Williamson added.

Also of note, Zuckerberg on Wednesday stressed Facebook’s strong presence among sports fans -- noting that roughly 650 million users are currently connected to a sports Page. For this year’s Super Bowl, meanwhile, more than 65 million people generated more than 265 million interactions on Facebook, according to internal estimates.

During the quarter, meanwhile, Facebook said it reached a new milestone of more than 4 billion daily video views, whilemore than 80,000 videos have now been embedded on third party Web sites.

Among other ad products launched during the first quarter, Facebook rolled out Product Ads -- a new format for brands to show off multiple offerings, and in some cases, their entire inventory. To avoid overwhelming users -- and improve conversion rates -- Facebook said the ads would be highly targeted and customizable.

Also during the quarter, Facebook’s Atlas unit tapped Merkle and its wealth of customer relationship marketing (CRM) data. The alliance followed a similar pact between Facebook’s ad targeting and measurement platform and Havas Media Group.

Sandberg on Wednesday noted the increased adoption of Facebook’s targeting tools like Custom Audiences and Conversion Tracking.

Globally, more than 1.4 billion people now use Facebook’s core service. In addition, some 800 million people use WhatsApp; 700 million people use Groups; and approximately 600 million use Messenger.

Instagram currently boasts more than 300 million monthly members, and more than 200 million daily active users.