Determining Quality Websites

The goal of search engines is to match up searchers with quality websites and the information that the user is looking for. Under that assumption, shouldn’t search engines attempt to determine what’s a quality website outside of pure linking and content factors? What about:

1. being hosted on a dedicated IP
2. outbound links (these might be the biggest IMHO — not only to put your site in its topical neighborhood, but also just a plain old GOOD neighorhood)
3. doctype and language metadata in your header
4. valid code
5. invalid code but linking to the W3C validator (”we tried!”)
6. existence of a print stylesheet
7. a file named privacy.*
8. the existence of Access keys (accessibility best practice)
9. a ’skip navigation’ link (accessibility best practice)
10. Long domain registration period
11. Consistent link acquisition over time
12. Low link rot
13. Few broken links
14. User repeat visits
15. Adds or notes on personalized search results
16. Visitor duration - though often argued by SEO that like to rationalize their links’ pages as “resources”
17. High level of users that bookmark the page
18. Steady SERP position
19. CTR of links
20. DMOZ
    listing (yes, I hate this too, but I think a lot of us have seen decent
    evidence of it at least to speculate it a quality indicator)

I like 2, 3, 4, 11, 16 and 19. The rest seem too arbitrary to adequately go by.