Yes along with beta refreshes from the Messenger and Mail teams, this week will also see the opening of Windows Live Expo to a much wider audience. Up until now, the beta has been limited to Microsoft employees and a few other email domains, despite the signin page being freely accessible at expo.live.com.
Now we will see Expo being rolled out to users in approximately 50 major cities in the USA, so if you haven't signed up yet for it, this would probably be a good time! Unfortunately, as has been confirmed by the team on their blog, Expo will not be going global for a while yet.
Along with the standard functionality of Expo (buying, selling, trading) there are several features that make it standout compared to its more established competitors. One of these is the implementation of exposure and location sliders, allowing the user to set who the listing can be viewed by, and how local they must be. These vary respectively from Messenger to Everyone and Your City to Global.
Although not appearing to be active yet, Expo also features integration with MSN Spaces, allowing users to display their recent listings in a module on their Space. With the beta refresh of Windows Live Messenger coming this week, I'm expecting to see some form of Expo integration in there too via gleams and contact cards.