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)