Have you read your EULA?
I am a big proponent of knowing what you agree to, and even then I do not read all the End User Licence Agreements (EULA) that I agree to (What is a EULA?). Recently I stumbled across an article in Wired with excerpts / examples from some current EULA's .
3. All commerce, not limited to lemonade purchases, will be conducted through StreetBook. Customers must have StreetBook accounts even if they live on a street owned and operated by a StreetBook competitor. StreetBook will place a hold on all moneys in order to collect interest, and might place a longer hold if any party makes claims of fraud or activities that violate this agreement or any other residential use agreement.
[This provision is inspired by the business models of online payment services.]
4. A $100 annual fee must be paid to be a lemonade stand developer.
[This is again an example of following in the successful footsteps of app stores.]
Here is more detail,
This EULA Will Make You Rethink Every App and Online Service You Use
Next time you sign up for a service, take a look at the End User Licence Agreement.