The easiest way to use Sidewinder is as a standalone desktop web applications viewer. A desktop web application--or what we often call an internet-facing desktop application--is simply an XHTML document that is running in a purpose-built container, rather than a standard web browser. Running web applications in this way is useful since it allows us to interact with the application as something distinct from our browsing experience.
For example, say we have a simple web page that tells us when the next train home is; we could open this page in our web browser and look at it periodically for updates, but why not take the same web page and dock it to the side of the screen, and make it automatically hide when we're not looking at it? This is the kind of functionality we would expect from a desktop application, and by using Sidewinder, it's now the kind of functionality we can use with our web applications.
Let's look at some examples.