Earlier today, Facebook posted an impressive set of results for Q3, with mobile driving its growth in terms of both userbase and revenues. 

73.4 of Facebook MAUs (Mobile Active Users) are mobile users, while 21.3 per cent – 254m people – exclusively access the social network from mobile devices. And ad revenues have followed suit, with mobile ads making up 44 per cent of the companys total sales, a total of $882m (£550m).

According to eMarketer, Facebook will account for 15.8 per cent of worldwide mobile ad spend in 2013 – up from 5.4 per cent share last year. That jump is reflective of just how much “Facebook has evolved over the last year”, as CEO Mark Zuckerberg put it on the companys earnings call.

In fact, Facebook is approaching the point where the majority of its money actually comes from mobile, as it predicted in Q2.

“It is quite certain that next quarter will be the first ever where Facebooks mobile business surpasses its online,” commented Sephi Shapira, CEO of mobile ad firm MassiveImpact. “This is a clear indication of the huge potential that the constantly evolving mobile ecosystem holds for new comers that position themselves correctly.”

However, its worth noting that this switch isnt entirely due to Facebook growth on mobile. Its desktop revenues actually dipped in Q3, down $26m on the previous quarter to $918m. Its a similar story in terms of users:

“In Q3, for the first time, daily access on web declined year-over-year, albeit very modestly,” CFO David Ebersman admitted on the call. The social network actually saw a overall drop in daily users in the US, most prominently among younger teens – though Ebersman said that “monthly user numbers remain steady and overall engagement on Facebook remains strong”.

All earning call quotations taken from SeekingAlphas transcript.