Why should I provide any personal information to a service for which I am not offered any services or products? Let me explain. If I use the Mozilla browser and use a social network such as Facebook, I am using a service to talk to people, to get information.
I do not have a business return as such. The opposite is true when I register on my bank's virtual site, for example, and I buy books on Amazon, since I need to have merchandise delivered. If I need to make transactions through my bank, then it makes sense that I provide personal information.
Why should I provide information from the outset? If I do not need to provide information for this type of service, then why is the provider making the effort to collect what little information it can to which I never consented?