Dithering is essentially a method for trying to make an image look good while reducing the number of colors it uses.
Dither it! was inspired by a blog post from a site called Low-tech Magazine about how to reduce the energy usage associated with running websites. One method they discussed was to reduce full color images to dithered images with very few colors. Ensuing comments clarified that there are other, more modern ways to compress images which achieve small file sizes while maintaining color, but I still think it is a fun technique that looks cool and is interesting to learn about.

Content management and web site publishing for photographers