Don Norman on Queues
In the latest issue of Interactions, Don Norman explores the parallels between queues and interaction design. While he views this primarily as a metaphor, I think service designers can view the same subject matter without the abstraction:
Whenever two systems must interact, unless every event of one is perfectly synchronized with the events of the other, one system is going to have to wait. If the receiving system is ready first, it must delay, waiting for something to happen. If it is ready last, then if earlier arriving events are not to be lost, there must be a memory system to hold them. These memory systems have a variety of names depending upon the domain: memories, queues, buffers, inventory, waiting rooms, stock, and even books on a bookshelf (awaiting readers), food in the pantry (awaiting cooks and eaters), and any items that are stockpiled, awaiting use.
[via Pasta & Vinegar]