I've been doing some beta testing for microsoft recently, apart from the time I did WLM, live and IE7, I've now started to try out expo and wallop.
Expo is a kind of digital cork board like you'd get at a community center. Aka another craigslist, only this one is global and pretty slick.
you can look for items, sell them give them away for free, or simply ask for them. Not only items though, pretty much anything that can be given and recieved can and will be on expo!
The nice feature is the search, as you can search for items say, 50miles from your house if you dont want to pay so much on postage or driving to collect stuff.
Wallop is a kind of web 2.0 social network thing, seem's they've been hot on the trails of web 2.0 down at the live labs. Anyway, i've only just got my invite, and just started to mess with it, but it seems all flash and smooth and generally pretty. As far as use goes, that is yet to be proven, so far it's been really hard to use, and damned awkward!
More news on it later
Check out my wallop here.