The problem with business models like readyforzero's 'sell our users information for money' is that it relies on users not realising that this will happen.<p>Users let sites like readyforzero access their personal information; if they, say, put on their front page 'It's free because we sell information on your credit card transactions so businesses can decide not to offer you credit if they look too bad', most users probably wouldn't sign up - they want to make their credit rating better, not risk making it worse.<p>Relying on consumers not knowing about business practices is not a sustainable business plan for a model that needs high numbers of users to be profitable.