Many SEO topics are like good games – you can learn the basics in a few hours, but really mastering them can take years.
One topic that seems simple but that generates a ton of questions here on SEOmoz is URLs: How to construct them, how to optimize them, what the pieces are, etc. In the spirit of great SEOmoz cheat sheets like Danny’s web developer cheat sheet, I’ve decided to put together a 1-page guide to all things URL.
Courtesy of Dr. Pete, www.seomoz.org/blog