They talk of hashtags and I think these must be small electronic tracking devices affixed to the legs of Tweeters caught using hash, so that they can subsequently be more easily followed.

It is a land of thin glass walls with almost no privacy, Tweets are blared out of the public address system all the time, like a noisy train station so any nosey-parker can listen in on conversations and everything is recorded, by hidden scribes who will reveal at the touch of a click or a magnifying glass, incriminating statements you made years ago which you though were safely forgotten. {I'm told that WIVES do this too in real-space, but at least they keep it in the family}.

Occasionally however you find thick concrete block-houses which you cannot see into with nasty big bouncers on the door who demand to know your business and won't let you in until the Master approves you.