Facebook bought popular texting service WhatsApp last week . By adding voice calls to its mobile service . Last week , Facebook shocked the business world when it announced it was buying WhatsApp for up to $ 19 billion in cash and stock -- by far the social network 's largest acquisition to date . Facebook announces the plan at Mobile World Congress in Spain .
Facebook bought popular texting service WhatsApp last week . By adding voice calls to its mobile service . Facebook announces the plan at Mobile World Congress in Spain .