@fon
yes you can be tracked by any number of different schemes every day. Though most of them you can choose to not use, this system you can't choose to not use it as it taps your data stream directly. All of your stream, regardless of what port you are using - right now they're restricting themselves to port 80.
The reason why we are complaining about this one is the scope of it - this technology can be used to "sanitise" the contents of what you are reading in order to remove passages that they don't like. It can be used to alter that which you are submitting to the net.
It can be used to force you into paying more for access to certain pages - I'm sure the government would love to block everyone from accessing 4chan/b/ for example.
At the moment, they are only using it to collect behavioural activity, which IS identifiable even if it doesn't have your name on it, in order to sell advertising. Mission creep will always set in and you can bet the phorm we see today will be different in what it tracks to the phorm of tomorrow. They're profiting from your activities while not giving you a share of the pie - where is the incentive to use? And a measly £4 off really doesn't cut it.
Then we get the "even if you opt out, you're still profiled" issue to deal with.
This all contributes to a massive breach of your basic right to privacy and your right to freedom (since the potential for censorship is massive with this technology) as well as the potential to see you being persecuted for the type of information you consume.
Sure, it's over worrying quite a bit, but to be blunt the price of freedom is in being ever vigilent against schemes like this so that you don't lose that which is of extreme importance to you (freedom and privacy).