How Google works? a little Algo revealed

It's an interesting formula, Google Algo changes fast and even if they don't, we don't even know whats the formula behind. I found A Little Piece of the Google Algorithm - Revealed:

GoogleScore = (KW Usage Score * 0.3) + (Domain Strength * 0.25) + (Inbound Link Score * 0.25) + (User Data * 0.1) + (Content Quality Score * 0.1) + (Manual Boosts) - (Automated & Manual Penalties)

KW Usage Factors:

• KW in title tag
• KW in header tags
• KW in document text
• KW in internal links pointing to the page
• KW in domain and/or URL

Domain Strength

• Registration history
• Domain age
• Strength of links pointing to the domain
• Topical neighborhood of domain based on inlinks & outlinks
• Historical use & links pattern to domain

Inbound Link Score

• Age of links
• Quality of domains sending links
• Quality of pages sending links
• Anchor text of links
• Link quantity/weight metric (Pagerank or a variation)
• Subject matter of linking pages/sites

User Data

• Historical CTR to page in SERPs
• Time users spend on page
• Search requests for URL/domain
• Historical visits/use of URL/domain by users GG can monitor (toolbar, wifi, analytics, etc.)

Content Quality Score

• Potentially given by hand for popular queries/pages
• Provided by Google raters (remember Henk?)
• Machine-algos for rating text quality/readability/etc