D3-Cloud is a beautiful and open sourced implementation of word clouds that are familiar from Wordle.com.
It is built with the D3.js library, uses HTML5 canvas for drawing the output and works asynchronously for a good performance.
The size of the cloud, font used, font-size, padding and more stuff can be customized.
Also, a web-based word generator with SVG + PNG downloads is provided.
Compatibility: All Modern Browsers