If you look at many online terms of service, they reserve the right to change the terms at any time. Some force you to re-agree to the terms -- but others don't. In the past, courts have ruled that if someone didn't agree to the changed terms, the new terms
could be found to be unenforceable, but a recent decision has gone much further, effectively saying that the entire terms of service are void if they claim they can be changed at any time. Sent in by Blake, the ruling said that Blockbuster's online terms of service were "illusory" and unenforceable
because it included a clause saying it could change the terms at any time. So, even though the term it was trying to enforce was
in the terms that the person agreed to, the court found the entire terms unenforceable. This is quite a ruling that could have a pretty major impact on any online service that has terms that insist they can change at any time. While it's just a district court ruling and may be reversed on appeal, it's something anyone running an online service should pay attention to.