I totally agree Ari! If it helps them to track down terrorists, paedophiles, fraudsters or other criminals via their computers, I'm all for it. Like you say: the innocent have nothing to fear. So what if someone knows which websites you've been looking at - does it really matter? If they can target (and hopefully catch) some of the paedophiles who are grooming our children/grandchildren over the internet, surely that's a good thing? Also, I am sure we all get 'dodgy' e mails every day from scammers pretending to be legitimate sites and attempting to get our personal details; I've recently had over a dozen, supposedly from Paypal, to name only one.
I am sure there will be many who will complain about invasion of privacy etc. but I'm betting some of these will be the same ones who moan that the police aren't doing enough to catch the criminals when something awful happens! A case of you're damned if you do and damned if you don't. I believe they need to do this. At least this way they'll stop some of them.