What is desktop security?

After Internet is common, people notice that there is network security and their network has potential issue of being attack from Internet. And security company starts to develope network security to provide one's network. Later on, people make use of Internet technology to develop Intranet and local area network becomes more and more common. However, another security concern arise, as attack may not be come from out of the (local) network, but within the (local) network . Security company finds that they need to have a completely new idea to protect machine, so that's why they develop desktop security. Simply speaking the security protection should be reside on the desktop instead of the network boundary. By doing so, it can protect attack from both outside and inside the network. Today's desktop antivirus software, firewall etc are examples of this concept.