Most contracts involve a signature of some sort—you have to sign your name or provide an electronic signature, provide a personal identification number, or click “Accept”. These are all purposeful acts and constitute active agreement to a contract. But it’s also possible to passively agree to a contract, for which you don’t really need to do anything purposeful.
Som contracts (particularly for internet services) only require that a person use the service, regardless of whether any notice of the agreement has been provided. (Usually you can find notice in the Terms of Use for a web site or service, but you often don’t need to actively agree to them.) Take, for example, the following provision from the Terms of Service from Google Maps:
By downloading, installing, or using the Google Earth software, accessing or using the Google Maps service, or accessing or using any of the content available within the Products, you agree to be bound by the following….
When you navigate to Google Maps, there is no window that pops up requiring you to agree to the terms of service—either once, or every time you use it. But according to the Google Maps Terms of Service, simply accessing or using Google Maps binds you to the entire Terms of Service.
Legally, this is considered acceptance by performance, and all that is needed to accept the offer of one party is to perform according to the offer. Depending on the circumstances, full performance may not be needed for the acceptance to be valid; simply beginning to perform will be enough to be considered acceptance (thereby creating a binding contract).
What this means for casual web surfers is that it doesn’t matter if there is no requirement to accept terms of service for a web service; often, simply using the web service binds you to the terms of service because you are “performing” according to the offer extended by the service. So keep this in mind when using services on the web, or anywhere else. It’s not hard to be bound by a contract—even when you don’t know about it.
(photo: http://www.flickr.com/photos/freemind/)


