Rand Fishkin and SEOmoz polled 132 SEO experts with data from over 10,000 Google search results, and have attempted to rank the importance of ranking signals. It’s not confirmed fact, obviously. Google won’t provide such information, but I suppose the next best thing is the collective opinion of a large group of people who make their livings getting sites to rank in search engines, and Fishkin has put together an impressive presentation.
You can view the entire presentation here, but I’ve pulled out a few key slides that basically sum up the findings.
The factors are actually broken down into the following subsets, where each is ranked against other related factors: overall algorithmic factors, page-specific link signals, domain-wide link signals, on-page signals, domain name match signals, social signals, and highest positively + negatively correlated metrics overall.
The results find that page-level link metrics are the top algorithmic factors (22%), followed by domain-level, link authority features (21%). This is similar to the same SEOmoz poll for 2009, but there is a huge difference in the numbers, indicating that experts are less certain that page-level link metrics are as important. In 2009, they accounted for 43%.
According to Fishkin, the main takeaways here are that SEOs believe the power of links has declined, that diversity of links is greater than raw quantity, and that the exact match anchor text appears slightly less well-correlated than partial anchor text in external links.
Domain-wide link signals are cited as metrics based on links that point to anywhere on the ranking domain.
Here is what the poll looked like in this department:
The report compares followed vs. nofollowed links to the domain and page, finding that nofollow links may indeed help with rankings: