MENLO PARK, CA: The importance of mobile to Facebook has been underlined by fourth quarter results which show that advertising revenues through this channel doubled in a year and are now delivering more than two thirds of the total.

In an earnings call, company executives updated user figures, revealing that 1.39bn people use Facebook each month with 1.19bn doing so via mobile; some 526m access Facebook solely from mobile devices.

These figures had helped drive the increase in mobile ad revenue, which accounted for 69% of the fourth quarter total of $3.6bn, up from 53% a year earlier.

COO Sheryl Sandberg saw plenty of scope to grow those figures further. "We get 20% of people's time on mobile phone in the US between Facebook and Instagram," she said. "We don't get close to that in terms of anyone's marketing spend."

She also noted how the shift to mobile was altering the way people consumed video, with the number of video posts per person rising sharply in the course of the previous year – up 75% globally and 94% in the US.

"Today, over 50% of people in the US who come to Facebook daily watch at least one video per day and globally over 65% of Facebook video views occur on mobile," Sandberg stated.

The fourth quarter also saw the roll out of Instagram ads to new markets in Canada and Australia, with Sandberg reporting encouraging results: a series of videos for clothing retailer Banana Republic "drove a 23 point lift in ad recall".

She expected that in the longer term "Instagram will become core to advertisers and mobile brand building efforts".

As well as the growing importance of video Sandberg was at pains to stress improvements in measurement.

"When I sit down with clients at the beginning of this year compared to last year, we have more actual case studies of marketing we've done with them," she said. "And I think across the board, we're showing very healthy, very competitive ROI."

Wired observed that Facebook's success might also be related to that of Apple, which has just reported record profits, driven largely by sales of its latest iPhones with bigger screens.

"On those screens, Facebook's ads look better than ever," said Wired.

Data sourced from Seeking Alpha, Wired; additional content by Warc staff