Re: "people already hand over masses of info to private firms"...
I rather fear that the reality is that you have handed over more data than you think. I wouldn't be surprised if even the more privacy-conscious among us have had data taken by stealth. So many things we do - using a mobile phone, using a credit or debit card, etc. are practically unavoidable in this day and age, and all are opportunities for someone somewhere to scrape a bit of data about us....tans pis.