Facebook CEO Mark Zuckerberg’s own words play a starring role in the government’s case to break up his social network.“ It is better to buy than compete,” he allegedly wrote in an email in 2008, according to the lawsuit. Four years later, after Facebook purchased what he had called a “very disruptive” photo-sharing app, he celebrated by explaining to a colleague in another email: “Instagram was our threat. … One thing about startups though is you can often acquire them.”