Top 5 Ranking Factors

1. #
Keyword Focused Anchor Text from External Links
73% very high importance
2.
External Link Popularity (quantity/quality of external links)
71% very high importance

3. Diversity of Link Sources (links from many unique root domains)
67% very high importance

4. Keyword Use Anywhere in the Title Tag
66% very high importance

5. Trustworthiness of the Domain Based on Link Distance from Trusted Domains (e.g. TrustRank, Domain mozTrust, etc.)
66% very high importance

Top 5 Negative Ranking Factors

1. Cloaking by Cookie Detection 16.3% strong contention
2. Cloaking by JavaScript/Rich Media Support Detection 15.4% moderate contention
3. Hiding Text with same/similar colored text/background 15.3% moderate contention
4. Cloaking by IP Address 15.3% moderate contention
5. Cloaking by User Agent 15.2% moderate contention

Seeo more at http://www.seomoz.org/article/search-ranking-factors

positive indicators of quality:

* popularity of the site,
* Implied popularity of the site,
* tagging of the site,
* References to the site by other sources,
* A pagerank of the site, and;
* Other indicators could also be use

Hi,

I dont hear till now about negative ranking factor.

Negative means you site banned you can never promote your site after that.

Thanks