Bill Slawski at

SEO by the Sea

has an interesting post which gives an insight into how Google’s Blog Search ranks its results. He has come across a patent application by Google which explains some of the ranking factors.

The patent application, ‘Ranking Blog Documents’, shows how Google ranks blogs according to searchers’ queries based upon a combination of relevance and quality scores.

Positive ranking factors include:

  • How many blogrolls list the blog – especially from high-quality blogrolls or blogrolls of respected bloggers.
  • Links from other sources – including mail and chats.
  • How well tags are used to categorize a post.

  • PageRank

  • The number of subscribers to your blog feed -  using data gathered from feed readers.
  • Clicks in search results.

Factors which may have a negative effect on ranking:

  • Automated posting – an anti-spam measure.
  • Different content between the site and the feed – an indication of a low quality/spam blog.
  • The amount of duplicate content. 
  • Using words and phrases that appear frequently in spam blogs.
  • Posts that have identical size.
  • Linking to a single web page -  “If the number of links to any single external site exceeds a threshold, this can be a negative indication of quality of the blog document.”
  • The location/quantity of ads – if ads are seen in the recent posts of a blog, they could be considered a negative quality factor.