[two23]

Of course they can. Remember Carnivore?
https://en.wikipedia.org/wiki/Carnivore_%28software%29

[sdcraigo]

“Of course they can. Remember Carnivore?”

And Echelon:

https://en.wikipedia.org/wiki/ECHELON

ECHELON was capable of interception and content inspection of telephone calls, fax, e-mail and other data traffic globally through the interception of communication bearers including satellite transmission, public switched telephone networks (which once carried most Internet traffic) and microwave links.