Calling WhatsApp as a great fit in its plans to connect the next five billion, Zuckerberg said the buyout is "worth more than USD 19 billion."
"Already almost half-a-billion people love using WhatsApp for messaging and it's the most engaging app we've ever seen exist on mobile so far. About 70 per cent of its users use it everyday. We see WhatsApp is on path to connecting over a billion people and very few services can reach that level," he said at the Mobile World Congress here.
Asked if the company would again bid to acquire Snapchat, Zuckerberg said, "No. After buying a company for USD 16 billion, you are probably done for a while."
Last year, Facebook attempted to acquire photo sharing app Snapchat. According to reports, Snapchat turned down the USD 3 billion offer.
On privacy concerns, Zuckerberg said the NSA issue is "a real issue, especially for American Internet companies".
"Trust is just such an important thing when you're thinking about using any service where you're going to share important and personal information.
He added that Facebook continues to work to be sure we can share everything that the government asks for.
"The government kind of blew it on this. Governments have a responsibility to protect folks and to also be transparent about what they're doing and I think they've just been way over the line in terms of sharing what they are doing," he said.
Zuckerberg's debut at the show, one of the biggest events in the mobility industry, highlights the importance of mobile to the future of the social media giant.
Facebook is betting on emerging markets like India, which is a "key source" of growth for the Menlo Park-headquartered firm, as an increasing number of users log onto the site through mobile handsets.
The monthly active users (MAUs) in India stood at 93 million at the end of December 2013, of which 75 million logged in through their mobile phones.
"Facebook has clearly been prioritising its mobile strategy and mobile applications as its revenue and user growth have accelerated given increased use of Facebook on mobile," research firm IDC said.
WhatsApp can help Facebook expand broader and deeper into many mature and emerging markets, allowing it to leverage these network effects to drive deeper understanding of usage and drive engagement (and longer-term revenue) across its applications, it added.