Velocity: A Distributed In-Memory Cache from Microsoft
Like memcached, you can think of Velocity as a giant hash table that can run on multiple servers which automatically handles maintaining the balance of objects hashed to each server and transparently fetches/removes objects from over the network if they aren’t on the same machine that is accessing an object in the hash table. In addition, you can add and remove servers from the cluster and the cache automatically rebalances itself.
Microsoft’s answer to Memcached