Facebook's monetization plans though are harder to gauge. During the conference call, both Zuckerberg and WhatsApp CEO Jan Koum said their focus now would be on growing users, and that ads would not be the best way to make money within a messaging service. WhatsApp does offer a paid subscription model.
Facebook Chief Financial Officer David Ebersman said the company did not see any regulatory issues under the deal, and that it was expected to close later in 2014.
Meanwhile, although mobile operators still make money on text and on traditional voice calls, those services play a shrinking role in their overall business as alternatives sprout up, analysts said.
"The horse has already left the stable on this one," said Phil Marshall of Tolaga Research. Some carriers, including the big U.S. operators seem to be acknowledging this by structuring most plans with unlimited voice and text.
The tide has probably already turned against telecommunications carriers, the original providers of real-time communications. While Skype and other voice apps ate into minutes, Internet-based "over the top" services such as WhatsApp also overtook carriers in text-message volume in 2012, research company Informa Telecoms & Media reported last year. That year, the OTT players carried an average of 19.1 billion messages per day compared with 17.6 billion daily on SMS.
(Stephen Lawson in San Francisco contributed to this report)