This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Basically it just means that you need multiple computers to talk to one another while running the program.
Most modern distributed programs use RMI, CORBA, Jini, or some other system to have the objects in their program actually talk to one another, as opposed to building systems that talk to one another, as this usually involves duplicating data.
Write once, run anywhere, because there's nowhere to hide! - /. A.C.