When the Google search engine launched in 1998, it was revolutionary in how it allowed users to search the Web. Instead of just simply basing its results on subject matter, registration with the engine, and paid preference, Google pioneered an algorithm known as PageRank, which ranked a page based on how important that page was deemed to be in relation to all other pages on the Web. Importance was based partly on how many other pages linked to the page, and also on the ranked importance of those other pages. While there were other factors, these two methods made up the core of the algorithm used to decide how high or low a given page would appear in Google’s search results.

Immediately in became clear that if you could figure out the factors used in the Google search algorithms, you could manipulate the system to give preference to your own pages, a particularly attractive practice for sites who made ad revenue or sold products on their pages. And so Search Engine Optimization (SEO) was born.

However, in recent years Google has caught on to these strategies and it began a series of modifications to balance the playing field and ensure high-quality pages worked their way up in the search results. After all, Google also made its money on ad revenues, so it took every opportunity to ensure its users were getting the highest-quality results that would keep them coming back.

Here is a timeline of the improvements and updates Google has made to its search algorithms over the years to minimize the effects of optimization abuse:

February, 2011: Google launches the first version of Panda, an update to the company’s search algorithm that attempts to minimize the effects of SEO abuse. The effort was targeted at sites who took optimization to the extreme and pulled ranking away from more legitimate sites with more useful content. Where Google’s PageRank algorithm assigned rank to individual pages, Panda could penalize whole sections of sites, or even entire sites, for their shady manipulations of the search rankings. Although this sophisticated algorithm was based on human evaluations of what constituted quality and spam on Web sites, legitimate sites could still lose rank to sites that mirrored or stole their content from other sites, and Google came under criticism.

April, 2011: Google updates Panda to try to address some of the concerns and launches the algorithm across its worldwide network of servers.

April, 2012: Google launches a major update to its anti-manipulation algorithm and calls the new product Penguin. Penguin extends the functionality of Panda by targeting additional practices called “Black Hat SEO” by Google’s Webmaster Guidelines. Some of these include keyword stuffing, which is the process of loading down a page with hidden keywords and phrases meant to affect the rank a page is given. While many of these techniques have long been ignored by sophisticated modern search engines, thus rendering their usefulness void, Google Penguin assumes that the employment of the tactics reflects on the intent of the Webmaster and therefore the validity of the site.