Web browsers enable users to browse the Internet to access various web pages that contain information. Often times, web pages actually host other software applications, such as an online calendar, an online diary, a document management system, and so on. Web browsers commonly store information that is useful for a given application on the hard drive of a user in the form of what is called a “cookie”. For security reasons, a cookie can only be read by the specific web domain for which the cookie was set. As an example, a cookie might contain the user name and password for a user for accessing a particular web application. Such information might have been stored in the cookie after the user selected an option from within the web application to store his login credentials for faster access on future visits. In this example, the cookie is then read by the application on future visits to facilitate a quick login. This cookie containing the user's login credentials, however, cannot be read by a web application on a different domain than the domain for which the cookie was created.
As web development techniques have advanced, it has become easier for multiple applications to be displayed from within the same host application. The concept of displaying multiple applications together to the user in a single web page is often referred to as a “mash-up”. When multiple applications are hosted in a single page or application, they end up sharing the same host domain. This means that a first application on a particular host domain can access the cookies set by the second application on the particular host domain because they are both running on the same domain. There are times when this is not desirable for security and privacy reasons, such as when the applications are supported by totally separate companies and/or individuals.