In this blog post, no back story, just pure UML today.
In this case “Create an Account” is used by a Gamer coming to your site. The “Create an Account” is included in the User Profile and Security Use Cases (at least at this point of analysis). Now both the User Profile and Security, in a normally running business, would be used for many purposes. For example the User Profile would used for the customers, like the Gamer, it would also be used for roles such as BackOffice worker (accountants, executives, etc.), Developer, and so forth. With respect to security, the security model would function the same for the entire corporation, different security models are weaker.