Earlier quoted context omitted.
Users already opt into using a service like WhatsApp. They are presented with TOS on first use / account creation. Whatsapp changed their TOS and presented the new TOS to existing users when they first opened the app after the change. Doesn't this already satisfy your requirements? It is, of course, well known that users never read TOS / EULA for software or services.
> WhatsApp I'm not talking about WhatsApp. > users never read TOS / EULA Then the user hasn't given informed consent! It's the responsibility of the collecting party to make sure that the user is aware of all aspects of the transaction.
Should the user be required to correctly answer some quiz questions about the TOS every time they use the product? I don't think any users would agree to that, for any product.
Do you have a positive example of how to do this successfully?