The NCSA httpd 0.4 release in 1993 announced support for Group Annotations, which was basically this. So all of you "I had this idea four years ago" people need to get in line behind Marc Andreesen, who had this idea, dear god, 16 years ago.
It never really took off--I think even though httpd supported annotations, I don't think Mosaic itself ever really did.
A police officer can stop and question you in the street or a park or other outside place if s/he suspects you of committing an offence or believes that you have witnessed a possible offence. If you are stopped and questioned, you are expected to be co-operative. You must give your name and address to the officer if asked for it. If you don't, this is an offence and you could be arrested. If the police suspect you of committing an offence they may ask you for an explanation of your behaviour. You have the right to refuse to give an explanation. The police may then detain you for questioning for up to 6 hours; or arrest you for allegedly committing an offence.
They have additional powers of detention under new anti-terrorism legislation, but nothing as draconian as what has appeared in the US recently.
Yes there are loads of CCTV cams. Everywhere. They were introduced gradually over the past 20 years and have become such a part of the public concioussness and don't tend to cause general alarm even when displayed as such: http://www.art-for-a-change.com/News/eyes.htm/
Perhaps partly because they are also moderately effective in catching perpetrators of violent crime.
If you think that you're more free in the US, take another look around you my friend. Dig your secret police.
An algorithm must be seen to be believed. -- D.E. Knuth