Google, Yahoo, Microsoft, Twitter and Facebook have built global businesses that depend upon the security of the information that flows through their networks. They are very concerned that the revelations about NSA surveillance will undermine their global business. The recent leaks about NSA surveillance also caused them to distrust the government because they learned things about the surveillance that NSA did not tell them. Moreover, NSA's attempts to respond to their concerns by telling them that they are not spying on Americans does not help them to sustain a global business.
This article describes some of the things that they are doing to make their networks more secure and their efforts to lobby Congress which enabled NSA surveillance when it passed the Patriot Act in response to 9/11. Their business models, however, are based upon providing specific information to advertisers so that they can target potential customers. That makes their data more vulnerable to attack.