Privacy and networking sites
Although I don't have a FB account, I know that at least some of my friends have allowed FB to scan their email to create a list of their friends and acquaintances, which would include at least my name and email address. It would be easy for FB to use this data to create a pseudo profile for me which includes the details of many people that I know, and if this profile is given to third parties the question of permission would not arise, at least not my permission.
The behaviour of networking sites in harvesting information about people and their friends is quite frankly creepy and is getting worse as the sites think of new ways to get people to acknowledge friendships and pass on private information. For example Friends Reunited has started asking me to accept people whose profiles I've ever viewed as friends, and it's probably doing the same to them too. I didn't ask them to do that, and can't switch off this behaviour.
I would advise anyone to ditch these sites if they value their privacy, that of their friends, and their friendships.