and you thought Phorm was bad

[#1]

http://www.theregister.co.uk/2008/05/12/inside_comscore/

[#2]

And just as bad is that 6 days after your post, there has been no discussion of it. The Information Commissioner was wrong. We are not sleepwalking into a surveillance society, we have arrived. All that remains now is for the powers that be to lock the doors behind us, so that we cannot leave.

[#3]

Maybe because this is an opt in to do it, by  installing software. If you value your personal data so little, that is up to you.

[#4]

It's technically opt-in - but I expect the opt-in is buried in pages of licensing c**p.
Is this Windows only Spyware?
The following could be useful...
http://www.exterminate-it.com/malpedia/remove-marketscore