3. Direct from the Source:Danny Sullivan: If an article is retweeted or referenced much in Twitter, do you count that as a signal outside of finding any non-nofollowed links that may naturally result from it?Google: Yes, we do use it as a signal. It is used as a signal in our organic and news rankings. We also use it to enhance our news universal by marking how many people shared an article searchengineland.com/what-social-signals-do-google-bing-really-count-55389
4. What Might Be in a Tweet Algo? Number of Unique Tweeting Sources (Diversity)
20. Simplistic LDA Models Offer Higher Ranking Correlation than Any Other On-Page Metricwww.seomoz.org/blog/content-optimization-revisiting-topic-modeling-lda-our-labs-tool
21. #7: No One’s Taking Market Share from Google (Yet)