[throw0101a]

Twitter is a private company, which uses private servers and network switches, that communicates with ISPs and their private equipment, to send the information we're talking about.

Radio and TV use public resources (EM waves), to which they have been granted a government license, to transmit information, so the government can ask them to do certain things at times.

[AnimalMuppet]

And the phone company? Aren't they a private company that uses private wires?

[throw0101a]

Most phone companies (and cables) were granted local monopolies that allowed them to build out infrastructure and amortized the cost over decades. (Actually, in the US, there was only a phone company for a long time: AT&T.)

These were regulated monopolies.

[aspenmayer]

Which came first, the monopoly or the regulatory capture?