Google revolutionized web search in 1998 when it launched a search engine using links to rank pages.
Early search engines worked very much like search on your computer. When you search on your computer, you will see a list of all the files containing your search term in their content or filename. Search terms in the filename make it rank much higher in the results. The search term being multiple times in a document will make it rank higher too.
This sort of result was fine in the early days of the web, but soon there were too many results for many searches, and it was far too easy for webmasters to manipulate ranking by stuffing keywords into pages or filenames (URLs). Google became immediately popular because the top results using backlinks as a ranking factor were much better than the top results on alternative search engines (like Excite or Alta Vista).
Although Google’s algorithm has changed over the years and the size of the web has multiplied by a million, (and Google is less keen on getting you quickly to other websites,) links between pages remain an important ranking factor. To get those precious first places in Google you still usually need to get good links to your site – although what constitutes a good (or bad) link remains a contentious question.
In this article we will look at the importance of backlinks. In future articles we will have a look at how to audit your current backlink profile and the strategies you can use to gain links from other sites (producing great content is a good start).
What are backlinks exactly?
Backlinks are links that a URL receives from other URLs. Webpages contain links to other webpages. Links can be to other pages on your website (internal) or to pages on other sites (external). Links can be in the menu, on images or text – underlined blue text in a paragraph. Links can go to other webpages or to resources like images or PDF files. It is rare for a page to have no links.
You need to use tools that index the whole web to find what backlinks exist to your site from other sites.
The invention of PageRank
At the core of Google’s algorithm in 1998 was their patented PageRank. The name refers to its inventor Larry Page and not the webpages it was ranking.
The story is that Page had the idea for using links to rank pages after a conversation with his father about how academics rated themselves. Whereas the number of papers published was a traditional way to measure academic success, academics themselves preferred a better system: counting the number of times their papers were cited by other academics (citation counting).
Applying this to the web, Page imagined that “backlinks” (links received by a page) could be used like citations to rank pages by importance and create better search engine results. He launched the development of BackRub with Sergey Brin to prove this, creating an index of links between sites to quickly access the backlinks of any particular URL.
But just “counting backlinks” was not a good enough indicator to improve results and was, again, open to manipulation by webmasters. He therefore imagined a mathematical formula patented as PageRank to rank webpages based on the likelihood of a user finding them by randomly clicking on links during a visit to the web. A webpage that was unlikely to be discovered by random clicking would have a low rank. A webpage that would be frequently visited by random clicking would have a high rank.
BackRub became Google before it was launched to the general public and as Page’s PhD paper explained it integrated PageRank as a ranking factor alongside other traditional search engine ranking factors (such as the use of a keyword in the filename and page content) to produce new, better search results. The text used in the link between sites also became a ranking factor as important as the name of the file (URL) of the page itself.
In 2000, Google published a toolbar that gave a PageRank indicator from 0 to 10 for any page visited.
Although the 0 to 10 were just indicators of where a page was situated in PageRank, the notion of increasing PageRank on the scale of 0 to 10 became an important factor in SEO. A good link was considered as one from a page with a high PageRank.
Only the World’s most popular pages had a score of 10 – including the home page of google.com and whitehouse.gov. Unpopular pages had a score of 0. But there was also the possibility that a page had a score of 0 because Google hadn’t indexed the page yet or hadn’t calculated its PageRank (before 2002 Google recalculated PageRank only once a month).
Webmasters would look for pages with a high PageRank (6 or 7 was high for most webmasters) using the toolbar scores before requesting links from them. The theory behind PageRank meant that you would increase your own PageRank if pages with a high PageRank linked to you. Getting a link from the home page of Whitehouse.gov, for example, could boost your ranking massively for lots of keywords (but Bill Clinton never answered our calls).
Google stopped updating toolbar PageRank in 2013 and then removed access to PageRank in 2016. In sharing PageRank information, it inadvertently created an industry in the fabrication of sites that could sell links with PageRank to other sites. Although PageRank is no longer available publicly, it is still very much part of Google’s algorithm along with other signals obtained from links. It is therefore still interesting to try and calculate what PageRank you could get from links. Services like Majestic SEO and Moz index links like Google in an attempt to calculate an equivalent to PageRank.
Google warn against buying links that pass PageRank. In their help pages on link schemes, they warn that sites that use link schemes may see a negative impact in their rankings.
They also warn against using other popular techniques for increasing PageRank artificially such as guest blogging, link exchanges and offering products for reviews.
Over the years, Google have developed anti-spam algorithms to detect link schemes (one named Penguin is the best known) but they also review complaints manually.
Manual actions can be applied to sites by Google’s WebSpam team and these can result in pages being blacklisted from Google’s search results. Webmasters with an active Google Search Console account will receive an email notification if their site receives a manual action.
More reasons why links are important
It can be interesting to forget about PageRank when analyzing backlinks and managing link building campaigns.
Links from popular sites are by themselves great sources of traffic and conversions for your website. Being cited by certain sites – and linked from them – is also great for your reputation.
In future articles we will have a look at techniques for auditing your backlinks and ideas for obtaining more links.