Facebook purchases WhatsApp for $19 billion

Facebook has bought messaging app WhatsApp in a deal worth a total of $19bn in cash and shares.

It is the social networking giant's biggest acquisition to date.

WhatsApp has more than 450 million monthly users and is popular with people looking to avoid text-messaging charges.

Announcing the deal, Facebook founder Mark Zuckerberg described WhatsApp's services as "incredibly valuable".

WhatsApp allows users to send messages over internet connections, avoiding text messaging fees. The company claims it is currently registering one million new users a day.

It makes money by charging users a subscription fee of $1 per year, although it offers a free model as well.

Zuckerberg said the prospect of a deal was first floated just 11 days ago.

The Facebook founder said he believed WhatsApp was on track to have a billion users, but insisted he had no plans to place advertising on WhatsApp's interface, saying he did not think ads were the best way to make money from messaging systems.