Computer-aided design (CAD) programs and drawing applications such as Adobe Illustrator and CorelDraw produce graphics that don't look blocky when you zoom in on them. They scale up easily because they store geometric information about shapes and lines called vectors. These images are unlike pictures from paint programs or scanners, which are called bitmaps.
Viewer
A viewer assists your Web browser by handling files that the browser itself can't. Viewers can be any type of application, since they may be called upon to handle any kind of file--even sound files. Because it seems weird to use a viewer to play a sound file, some people prefer to call them helpers.
VPN (Virtual Private Network)
A Virtual Private Network, or VPN, is a private network of computers that's at least partially connected by public phone lines. A good example would be a private office LAN that allows users to log in remotely over the Internet (an open, public system). VPNs use encryption and secure protocols like PPTP to ensure that data transmissions are not intercepted by unauthorized parties.
VRML (Virtual Reality Modeling Language)
The World Wide Web isn't a linear experience like leafing through and reading a book. The Web enables you to jump around from place to place. But in most cases, you jump from one page-based site to another. HTML is the specification for page-oriented Web navigation. VRML is a 3D navigation specification, hammered out by Silicon Graphics, Intervista Software, and other organizations and individuals. It enables the creation of 3D sites (not necessarily just chat rooms, though this is one example of its use). Many sites and FAQs are devoted to discussing and showing off the technology. The specification is also available online.
