Facebook has closed its deal for messaging startup WhatsApp, after receiving the go-ahead from European Union regulators last week. WhatsApp CEO Jan Koum is now a Facebook board member, and has an "inducement grant" of stock currently worth $1.9 billion if he stays with the company for the next four years. The deal price, originally announced in February as $19 billion, has now risen to $21.8 billion, primarily because the value of Facebook stock has increased.