When Facebook bought WhatsApp for $22 billion in 2014, many observers scratched their heads. The smaller messaging platform had annual revenues in the low tens of millions. How could it be worth so much? Soon enough, however, Facebook’s logic became clear. While little noticed in the US, WhatsApp was already a juggernaut overseas, with hundreds of millions of users. In countries where Facebook was not as popular, the acquisition gave Mark Zuckerberg’s company an immediate foothold.

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