Question regarding purchasing an advertising thread

[DataSN.com]

The thread I purchase at here: http://www.dnforum.com/f60/ will be live and listed there for 30 days but what happens after the 30 days? It will not be listed there but it's still accessible right? I mean, people can still access the page if they have the address such as when they are searching from Google. It's just not listed on the board. Right?

A second question, how do I change my username? I see from here: http://www.dnforum.com/usernamechanges.php that it's not available any more?

and perhaps 3 people changed identities via a self-serve process from our store (which no longer allows you to change your username).

Where can I purchase a username change?

Thank you!