About 157 million of Facebook's 1.06 billion monthly active users access the site only on mobile devices, Facebook reported on its Q4 2012 earnings call today.
That's nearly 16 percent of its global user base that ONLY looks at the social network on a phone or a tablet, and never on an old fashioned-web page delivered on a desktop computer.
Unsurprisingly, Facebook now also collects 23 percent of its ad revenue from serving mobile ads. Total revenue was $1.59 billion, of which total ad revenue was $1.33 billion — implying that mobile revenue in Q4 was ~$300 million in the quarter.
Here's a chart of Facebook's mobile-only user base:
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