body: I was wondering what the legality is in the following situation.
  
  
  User signs up to site A. Just above the submit button user is notified that signing up to site A will also sign user up to site B (which they may not ever use). They have no choice.
  
  
  Site A is a blog and site B is an e-commerce site, both 'owned' by the same person.
  
  
  Is this, firstly, legal? If so, is it advised? Or should the user always have the option to choose whether they want to signup or not?
  
  
  
title: Automatic website signup without user consent