You can bet the farm that because of this all major online retailers have already started work to change their registration and ordering systems to implement a clickthrough rather than ticking a checkbox that says 'I agree'.
From reading the article linked to in tfa, a checkbox would work. Zappos's problem is that they just buried a link to the tos at the bottom left-hand corner of the page where no sane user would click.
You can bring any calculator you like to the midterm, as long as it doesn't dim the lights when you turn it on. -- Hepler, Systems Design 182