.... People knowledgeable about Google and Yahoo’s infrastructure say they believe that government spies bypassed the big Internet companies and hit them at a weak spot — the fiber-optic cables that connect data centers around the world and are owned by companies like Verizon Communications, the BT Group, the Vodafone Group and Level 3 Communications. In particular, fingers have been pointed at Level 3, the world’s largest so-called Internet backbone provider, whose cables are used by Google and Yahoo....