I got my beta invite today and tried out Windows Live Mesh.   There a are a couple similar services out there, not the least of which is Microsoft's own FolderShare.  But what makes Mesh interesting is the promise of true, seamless synchronization between PCs, mobile devices, and the web.  Your data just appears everywhere you want it to.  In theory, there's no need to use ActiveSync or any other tool to sync up.  Add to that a sharp, clean UI and this is an interesting new product (Excuse me, Technology Preview).

By sheer coincidence, I also played with Peer-to-Peer binding in Windows Communication Framework.  This lets you very easily expose your services in a P2P manner, and also uses the term "mesh" to describe the "cloud" into which your application is connecting.  I haven't quite figured out when I could use it in a typical line-of-business app, but there's something fun about being able to dress up your services in P2P, Message Queuing, or any of the other suits WCF offers, just by adjusting configuration.