This is part III of a series on the history and future of link-building. Previous parts can be found here and here.

Google was the biggest thing in search in the early 2000’s. Many of us who were optimizing for multiple search engines began to focus more and more on this emerging powerhouse. The use of pagerank gave us something to focus on. The other big search engines also began to use link signals as part of their algorithm, so link-building was part of any good search engine optimization effort.

Many people started using the Google toolbar to get more useful information about web pages. One piece of information available this way was a number from zero to ten that Google called PageRank. Any web page indexed by Google was given this number. The scale was exponential, so a page with PR 7 was far better than one with PR 6. The listed PageRank was not updated as frequently as the actual algorithm, but many early SEO practitioners treated it as gospel.

When we compiled lists of other web pages, whether as link partners, opportunities, or as part of competition research, we would generally use this pagerank number (PR) as a metric. It was also useful in tracking how Google saw different parts of our own websites.

But most of us understood that this number was only one factor. Relevance was usually more important. Often, if you did a search, the top listings on the results page would not have a highest pagerank.

Others saw it differently, and some began to charge for a link from a web page based on its reported pagerank. Giant pages full of links were already being sold as ways to increase your position in search results. But, for the most part, these link-farms were seen as spammy and never taken seriously by webmasters. Another model rose up, though. Based on the idea that pages with higher PageRank were worth more, this model promoted link-exchanges or purchased links from higher-value pages.

One of the leading websites using this practice was SearchKing. They would bring you high-value links and web traffic from one place if you reciprocated somewhere else.

Google didn’t like this much. The whole purpose of using inbound links to evaluate the quality of a web page was that such links indicated people genuinely valued the page. Allowing link-swaps and paid links to change that picture degraded the usefulness of search results.

In 2002 Google changed their algorithm in a way that lowered the pagerank of SearchKing and of many of the clients who were paying SearchKing for exactly the opposite effect. SearchKing filled suit against Google, but lost. Google claimed that it had a first amendment right to change its algorithm.

One thing that became clear, and should perhaps always have been clear: Google only uses links because it believes they signal actual user interest. The best in-bound links are those that provide value to the actual visitors of a website.