Think of tags as like a book index where you find words and which pages they are on, the same principle applies here. Although it's taken a stage further so it might not be the word, but the subject, so for example if you're looking for things to do with fractal gradients for example. A tag may bring back posts with gradient files, as well as posts that discuss gradients, or tutorials about them.

JWildfire Solid Render Lighting

Excellent guide to how lighting 3D models works in Jwildfire, Rick Sidwell goes through the different settings and how they change how your 3D model looks.