> Your continued use of the Service or Products after any 
  > modification to this Statement will constitute your 
  > acceptance of such modification and updates.

Is that even legal? I thought a contract required equal bargaining power, and explicit acceptance. If you have already purchased a good, and suddenly the terms change, I would think you would, at that point, have decidedly unequal bargaining power -- the company already has your money, and you either have to stop using the product, or agree to the terms. That doesn't seem "equal" at all.

I'm starting to think that any sort of B2C legal agreements, but particularly standard form contracts and similar documents like terms of service, EULAs and privacy policies, should be explicitly banned from including terms that essentially say the deal can be revised unilaterally and the customer is responsible for keeping an eye out for this. It's simply not a reasonable or practical arrangement for any normal person to do that, and it's the worst form of legalese CYA wording.

Perhaps, as with various other unreasonable or one-sided provisions, there should be a presumption under consumer protection laws that any such terms are invalid, that any substantial change in an agreement must have the customer's explicit, active consent, and that if the customer does not consent and this results in something they purchased no longer providing the expected benefit then the usual protections about broken purchases should apply. You'd have to be a bit careful, because sometimes these self-updating terms are used to deal with minor changes in the legal landscape that are formalities with no real impact on anyone, but that seems like the sort of thing a court could sensibly decide in the event of a dispute.

I don't think they are valid in most jurisdictions, explicit consent is required.

I suspect a lawyer might say you're right, though since most people aren't lawyers, the damage may be significant even from letting them include the terms in the first place.

More importantly, I don't think consent is sufficient in this sort of situation. It has to be a real choice, so even if you choose not to consent to the change, you're not then losing out on something you already paid for or otherwise giving up your normal legal consumer rights as a consequence.

In a situation where the continued effective functioning of a purchased item is dependent on some other facility, and that facility and the related functionality can be turned off if you don't accept the manufacturer/vendor moving the goalposts retrospectively, I don't see much ethical or practical difference between using this dependency as a lever to force a customer to accept revisions in some other aspect of the deal and just doing the other thing without their consent anyway.