Last 5th of June 2007 Google updated their Webmaster Guidelines, including the addition of hyperlinks to more detailed pages on specific quality guidelines.
If you’ve never read through the Webmaster Guidelines it’s a good exercise and something I need to do again so I can be up to date with the latest changes.
If you need more help in understanding the guidelines have a look at Patrick Sexton’s very useful resource Feed The Bot, which goes into greater detail than you’ll find at Google as well as providing links to additional resources. The only thing I don’t like about Feed The Bot is that I didn’t think of it first (Steven Bradley – a.k.a. vangogh).