Tutorial for JWildfire — Wfield Perlin Patterns And Image Mapping.Forgot to mention you can … Details
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.
The blob variation pushes and pulls the plane to make it look like a blob. Specifically, it takes a sine wave, wraps it into a circle, and uses that to distort the plane. The pictures below show respectively a sine wave, a radial sine wave (one wrapped into a circle), and a circular dc_perlin texture before and after applying blob.