Generally after posting my stuff I usually go trough a couple of months later and check snippets of my articles, allthough it is almost impossible from keeping someone from copying content, I have had some content of my own copied, but it did not really seem to affect my rankings and actually one of the sites that did eventually vanished.
My own perception from people copying content is that one, they are serious about what they are doing and two they wont last long in the business.
Rod