PRISM: How I would set up covertly monitor of a Country's Internet Traffic

If I worked for a government intelligence agency, and I was tasked to devise a way to monitor the public Internet traffic data covertly, I would target the source of the Internet connectivity provision. The source of the internet connectivity resides within the telecommunications operators (telcos) e.g BT, Virgin Media. AT&T. Many telcos double as ISPs, but its the telcos who ultimately provide access to the Internet to ISPs. An advantage in monitoring at the source is I don't need to tell or ask the permission to do so from a series of private companies, like Google, Facebook, Apple and Microsoft, as I can simply intercept and record all of the public's sent and received internet network traffic on route to these private companies.

Typically teleco companies provide fast Internet connectivity to their clients (ISPs) over fibre optic cables. If I were to split the light signals sent over these fibre optics cables, I could allow traffic to continue on its merry way completely uninterrupted, while at the same time copy the signal light down another cable, sending the signals to my a secret data centre, where I would simply copy the traffic data, put the data together and then analyse it. Could this splitting of fibre optic light communications be the origin of the name PRISM?

For a government it would be fairly simple to have your teleco operators sign up using secrecy laws, indeed many telcos in the West were originally operated by governments, and continue to be licensed by their government, therefore remain easy to leverage. This approach means the likes of Google, Microsoft, Apple and Facebook would never officially have to be asked and therefore officially know about the monitoring, hence their official denials about PRISM.

The only surprise I have with the PRISM media storm, is that people were actually surprised that this type of monitoring is conducted by their elected governments.  I am not a privacy nut, but its fairly obvious that most governments in the world monitor their citizens online usage.  The lure of big data monitoring of citizens was always going to be too good for government secret services to resist doing.