You found the class site. Good start!
Go ahead and set up your own blog (aka "Space" in Posterous-speak). Add a photo of yourself so I can start to connect your smile to your name. Then email a link to your page along with your name (whatever variation you'd like to be called this semester) to me (jhallden@gmu.edu) . Do this today.
Once the blog web addresses start rolling in, I'll add them to this main class site. Then you can subscribe to the rest of the class and use the Reader to track what everyone is doing. Easy!
And one last thing -- you need a first post. Find an interactive or animated map online that you really like (any topic). Depending on the site, you may be able to download the movie/animation to your machine and then upload it to Posterous. If so, great. If it is an interactive site, you probably cannot, so try to take a picture of the page (screen shots are crude but easy), post that to your blog along with a link to the actual page. With either approach, add a few sentences to the post explaining why you selected it. What about it caught your eye?