In the beginning, Google's search engine really wasn't all that good. This was back in the late 90s/early 00s, when search engines were little more than keyword-matching and link-counting machines. Ranking high in search results could be accomplished by essentially using a simple, two-step procedure
Step 1: Stuff your keyword phrase into your page/website as many times as possible.
Step 2: Get as many gosh-darn inbound links as you possibly could.
For those early "SEO gurus" who gamed the system -- achieving high rankings while adding little value for actual searchers -- the fun wouldn't last. Every time Google found a weakness in its ability to deliver relevant, high-quality search results, it made fixes to address it. Starting in 2003 with "Boston," major changes to its algorithm are adorned with names and made regularly.
To give you a snapshot of all of the algorithm changes that have been implemented over the years, we teamed up with Moz to create the infographic below.