The Google Webmaster Blog summarises them:

Quality guidelines – specific guidelines

* Avoid hidden text or hidden links.
* Don’t use cloaking or sneaky redirects.
* Don’t send automated queries to Google.
* Don’t load pages with irrelevant keywords.
* Don’t create multiple pages, subdomains, or domains with substantially duplicate content.
* Don’t create pages that install viruses, trojans, or other badware.
* Avoid “doorway” pages created just for search engines, or other “cookie cutter” approaches such as affiliate programs with little or no original content.
* If your site participates in an affiliate program, make sure that your site adds value. Provide unique and relevant content that gives users a reason to visit your site first.

I think they can be summarised by saying ‘don’t be dishonest, and don’t load your site with junk’. I’d say they were excellent principles to get your site to perform well on just about any major search engine.

Related posts:

1. How spiderable is your Web site?
2. Playing the Google Sandbox
3. Where should optimized content go on the page?