ISP (Internet Service Provider) is the internet companies who provide us internet connect as per our requirement. This question might come in your mind also that what ISP companies do Google and Facebook like big website use? So bear a thing in mind that they never use the normal ISP in there service.
Giant companies like Google and Facebook do what ISP do, not what ISP provides. They are building up their own network inside their data center using world’s most speedy wires Fiber Optic Cables which does the jobs much faster than a simple Ethernet Cables does. Also they open up mini data centers all over the world which is known as CDN (Content Delivery Network) Data Centers.
These techniques do Google and Facebook like giant web companies use instead of select an ISP for accessing internet and utilizing it to their huge resources.