Moz published their annual Search Engine Ranking Factors based on a survey of SEO experts. The SEO experts opinion of the most important factors in 2015 are:

1. Domain level linking (8.2 out of 10) – quality and quantity of links etc. to the entire domain
2. Page level linking (7.9) – quality and quantity of the link to the page, anchor text
3. Page level keyword and content (7.9) – content relevance to search term, content quality ranking factors, topic modeling factors
4. Page level keyword agnostic measures (6.6) – readability, content length, uniqueness, load speed, markup, https, etc..
5. Engagement data (6.6) – based on SERP clickstream data, visitor traffic and usage signals… on the page and domain level

This both reinforces the importance of links and also shows how search result rankings have evolved to include many other factors as significant and important determinants of search result rankings.

Related: Keeping Up with SEO Changes – Site Spam Flags Score from Moz – Why Don’t Search Results Screen Better by Date?