Mr Google, Matt Cutts, mentioned at PubCon recently that there are over 200 variables in the Google algorithm & although no-one but Google knows what they are exactly, we can have a reasonably good guess at many of them. In fact, WebmasterWorld have set themselves a challenge to list them all!

Here is what has been included so far:

Domain

• Age of domain
• History of domain
• Keywords in domain name
• IP address of domain
• Location of IP address / Server

Architecture

• HTML structure
• Use of Headers tags
• URL path
• Use of external CSS / JavaScript files

Content

• Keyword density of page
• Keywords in Title Tag
• Keywords in Meta Description (Not Meta Keywords)
• Keywords in header tags (H1, H2 etc)
• Keywords in body text
• Freshness of content

Per Inbound Link

• Quality of website inbound linking
• Quality of web page inbound linking
• Age of website
• Age of web page
• Relevancy of page’s content
• Location of link (Footer, Navigation, Body text)
• Anchor text of link
• Title attribute of link
• ALT tag of images linking
• Country specific top level domain
• Authority of top level domain (.edu, .gov)
• Location of server
• Authority links (CNN, BBC, etc)

Cluster of Links

• Uniqueness of class C IP address

Internal Cross Linking

• Number of internal links to page
• Location of link on page
• Anchor text of FIRST text link

Penalties

• Over optimisation
• Purchasing links
• Selling links
• Comment spamming
• Cloaking
• Hidden text
• Duplicate content
• Keyword stuffing
• Manual penalties

Miscellaneous

• JavaScript links
• No follow links

Pending

• Performance / Load of a website
• Speed of Javascript

Not included, but often focussed upon

• XML Sitemap (Aids the crawler but doesn’t help rankings)
• PageRank (General indicator of page’s performance)