By default, your application’s canvas page is publicly searchable by search engines and viewable by those not logged into Facebook. This makes it very important to ensure that your application’s canvas pages are tuned for Search Engine Optimization (SEO), so that others can use your app outside Facebook or are at least encouraged to log in and use your application.

All FBML is built to work on canvas pages even when the user is not logged in. To force a user to be logged in before using your app, use the <fb:is-logged-out/> tag, described in the next section.