To understand the importance of links in search engine rankings, consider the early research of Google founders Larry Page and Sergey Brin. Their Stanford University project, which they called “BackRub,” expanded on the foundation that, in academia, the more times a research paper was referenced by other research papers, the more authority the cited paper carried. (Wikipedia and other sources chronicle this project.)

Google’s first production server at the Computer History Museum.
Photo Credit: jurvetson

Taking that concept to the World Wide Web, Page and Brin set out to construct a search engine that utilized link structure (along with the actual anchor text in the hyperlinks that pages point to) to return relevant results, and to do so quickly and efficiently. PageRank — a play off of Larry’s last name –was introduced. “BackRub” — perhaps a play on back links? — became Google — for sure a play on googol — and the rest is history.

[Larry and Sergey’s Stanford paper, The Anatomy of a Large-Scale Hypertextual Web Search Engine, is a fascinating read into the backstory of Google. Amongst the talk of damping factors and mathematical formulas like PR(A) = (1-d) + d (PR(T1)/C(T1) + ... + PR(Tn)/C(Tn), the paper gives great insight into the duo’s thinking as it laid out its goal of “Bringing Order to the Web.”]

Now, let’s take that concept to your site. If you write about “rocket science” … and you include that phrase in page titles … and you have it in page headings … and you have links within your pages that include rocket science as the anchor text and point to other pages about the subject … then you’ve told your visitors, and the search engines, that one of the themes on your site is rocket science. Within reason, the more this phrase is naturally used in page content, titles, headings and hyperlinks, the better. Google knows this phrase is important to you, and it can begin to judge the importance of your site for that term.

Here’s where PageRank, external links and anchor text solidify your theme and can help establish your site as an authority on rocket science. When other sites and blogs and Tweets, etc., link to you with rocket science in the content of their pages and in the actual hyperlinks that point to your page, your site in essence receives votes for being important for that topic. (It’s one thing for you to write “we are the best at rocket science.” It’s another for someone else to write that “these guys are great at rocket science” and link to you for more information on that subject.) The more votes you receive the better you rank. And, more importantly, the “better” the vote (from a site which itself is an authority on the topic) the better your ranking.

Again, the concept can’t be abused. Excessive links from bad neighborhoods or from multiple domains controlled by the same owner or from other shady practices can lead to penalties. Like other SEO techniques, it shouldn’t be overdone, or forced, or spammed … but legitimate links from legitimate sites give a boost to your Google Juice … and everybody likes Google Juice, right?

Remember the premise of Google: Each time a given author was quoted as a reference in other academicians’ research papers, it was seen as a vote for the authority of that author. Now, simply carry that forward to the multi-billion-dollar external search engine: The more times a site is referenced, the more authority that site has, and the higher it ranks. Write good copy, optimize it well for on-page factors, and let the world vote on that content with links to your site.