Moz's study examined the top 50 Google search results for approximately 15,000 keywords. This allowed us to examine not only what factors correlate with higher search rankings, but also how frequently those characteristics are seen. The relationship between external links and rankings: 1. External links are almost always present for competitive searches: If you want to rank for anything that's even remotely competitive, the chances of finding a website ranking without external links is very rare indeed. 2. It's possible to rank individual pages without links: As long as your website itself is linked externally, it appears more than possible to rank individual pages on your site, even if those pages themselves don't have external links. That said, there's a strong relationship between links to a page, and that pages performance in search—so it's much better if the page actually does have external links. 3. More links correlate with higher rankings: It seems obvious, but the study confirmed the long-standing correlation between higher rankings and the number of external links found from unique websites. Get the full story at Moz