Facebook Inc shares have dipped from a record high after the world's biggest online social network again warned investors its advertising revenue growth would likely come down.
The warning on Wednesday appeared to outweigh Facebook's surging quarterly profit and revenue, fuelled by growth in its mobile ad business, which is still not showing much sign of slowing down as the company nears the five-year anniversary of its initial public offering.
Facebook said quarterly profit rose 76.6 per cent year-over year to $US3.06 billion ($A4.12 billion) and total revenue went up 49 per cent to $US8.03 billion.
Chief executive Mark Zuckerberg said in a statement it was a "good start to 2017".
However, Facebook's shares fell 2.7 per cent in after-hours trading to $US147.60.
They had closed at a record high of $US153.60 on Tuesday.
Chief financial officer David Wehner said after the earnings announcement the company expected its ad revenue growth to come down significantly over the rest of 2017, repeating prior company warnings it was hitting a limit in "ad load", or the number of ads it can squeeze onto users' pages before upsetting them.
The social media giant expects to generate $US31.94 billion in mobile ad revenue globally in 2017, up 42.1 per cent from a year earlier, according to research firm eMarketer.
That would give Facebook a 22.6 per cent share of the worldwide mobile ad market, with arch-rival Google of Alphabet Inc projected to be the leader with a 35.1 per cent share, according to eMarketer.
Facebook continued its march toward the two billion user threshold, saying it had about 1.94 billion people using its service monthly as of March 31.
That was up 17 per cent from a year earlier.
Analysts on average had expected monthly active users of 1.91 billion, according to financial data and analytics firm FactSet.
Earlier on Wednesday, Zuckerberg said the company would add 3000 people over the next year to monitor and remove murders, suicides and other inappropriate material from its network, which have become a threat to Facebook's valuable public image.
