Its called CRM stamina. (consumer relationship marketing)
It means that the site can contact you with follow up adverts, or sell your info on to other services. It's a cheap and easy way to gain a customers contact details, sadly, thats the way marketing is goin, so you'll just have to get used to it!
But I do actually agree that if everything is free, then it seems un-necessary
"It's often better to keep your mouth shut and let people think you're an idiot, than to open it and confirm their suspisions" - Noel Coward
