Moz has released the 2013 search engine ranking factors survey, which involved surveying 120 SEO professionals. The 120 individuals ranked different search factors to come up with interesting information that should be considered while optimizing a website for search engines.
Moz used over 14,000 keywords from Google AdWords across a number of categories and then extracted top 50 organic search results, post Penguin update in June. Search correlations were used to make an estimate of what is being used for the ranking algorithm in Google. The correlation was also based on the features present on higher ranking sites versus the features in lower ranking websites.
An interesting correlation found was that despite professionals knowing that over optimizing a keyword anchor text can be problematic for the site and give a sign of spamming, the correlation for exact and partial match was fairly high. However, SEOs believed that a diversity in the anchor text (including branded and non-branded items) was far more important than number of links.
On looking at on page keywords, a high correlation was found in the body text, H1 tags, and meta-description. The survey revealed that including keywords in title and on page is important.
The survey also revealed that rankings of exact match domains have declined in the past year, but correlation is still high. A few years ago, it was extremely important to have the keywords in the domain but it is not being practiced now.
Moz also said that social signals and their correlation with ranking factors are essential. It is interesting to know that Google +1's are ahead of the Facebook shares and tweets for the correlation factors. The survey however doesn't feel that social signals are of too much importance to Google search algorithm.Moz Comes Up with 2013 Search Ranking Factors Survey!,