No idea on CCTV stats as they have been employed in public spaces since as long as I can remember. From personal experience I can say that they don't prevent crime completely, but do seem effective at solving them.

Never seen this site before just seemed decent enough for this news, no issues with display here either.

As for the issue at hand: surveillance in public as by CCTV is completely different than surveillance at home as enacted by the security services and police. I think it's reasonable to assume little to no privacy in public (as that is what I'm used to), and certainly anything I was at home shouting out the window I would expect to be heard / intercepted, which is analogous to most interaction with the internet; but this is to the level of someone coming and sitting in my lounge, bedroom or bathroom, making notes and recording it.

Maybe, maybe I'll mention my plans to destroy western civilisation... Or more likely they'll end up with boring footage that they really have no need for, except possibly blackmail over throwaway jokes or hyperbolic comments taken out of context.