Twitter leads to some very good things too
If you don't use it you wouldn't understand, but what WM is talking about is that some twitter accounts are NOT those of individuals, but of companies/organisations, and yes, police forces.
Some of these may at times have merit - a police force tweeting 'we're out and about in this area today with speed cameras/checking road tax/insurance', might just give some people a jolt. Likewise 'we're patrolling the M27 in unmarked cars for dangerous driving'...
BUT, these accounts are being used by some as WM illustrated, daft individuals using the organisation's a/c to tweet daily trivial rubbish - and not so trivial too, things the general public should not be so aware of.
I barely use it, just once in a while will go and have a proper look, which doesn't give you a proper experience of it at all. The people who get the most out of it are those who use it daily. But don't imagine they're actually on there all day, for the most part they're not at all. If you follow a well-known actor, or journalist, whatever, you will generally find there's a pattern, a regular time of day/evening when they appear, just for 20 minutes or so.