Mac OS X Lion features multi-user remoting, offers inexpensive Windows Server alternative
Now, this isn't to say that Lion Server has an overwhelming feature set, but it's more than enough to run a home or small business network -- and when you compare it to the cost of a preconfigured Windows Home Server box or Small Business Server 2008, which can be hundreds of dollars, it becomes a very good deal indeed.
If we haven't sold you yet, check out a feature that 9to5 Mac has just discovered in Lion Server: multi-user remoting. Multi-user remoting means that someone can be sitting at a Mac with OS X Lion installed, and someone else can log in remotely without interrupting the current user. If you prefer Windows terminology, it's like running concurrent RDP sessions.
9to5 Mac goes on to mention that if you have MobileMe and combine it with Back to my Mac you should be able to have concurrent users logging in from all over the world. There might be some potential tie-ins with future versions of iOS, too!