Everybody uses Internet search engines such as Google or DuckDuckGo. We rely on them for answering all sorts of questions, even to conduct secondary research or literature reviews. But without knowing how they work, how do we know if we can trust them? How do we know if they're giving us reliable, trustworthy results? By understanding how they work, you can become an informed user.
In order to get the best results from a search engine, it's important to know how they work: how they actually find and retrieve information and how they present that information to you, including how they rank results. The actual technologies and underlying computer code are often closely guarded trade secrets, meaning that it's impossible to know exactly how they work, but from information provided through patent filings and other public sources, plus a bit of reverse engineering, we can get pretty close.
One very important consideration when using search engines is that the ranking of a page can be influenced by the website's owner. This is called "search engine optimization," or SEO, and it is a big business. Because of SEO, the top results of your search may not be the most relevant to you, but rather what the companies with the deepest pockets want you to see. Even though there are hundreds of companies that specialize in SEO and hundreds of do-it-yourself guides, there's nothing mysterious about how SEO works. This video provides a brief explanation of how SEO works:
In addition to increasing a website's ranking, SEO techniques can be used to suppress undesirable information from being displayed in the top page of results. Many companies avail themselves of services that specialize in sanitizing search results. This short video, despite being an advertisement for one of those services, explains the process. (Please note that this video advertisement is provided for informational purposes only; it does not constitute an endorsement or an approval by the Illinois Institute of Technology of any of the products, services, or opinions of the corporation or organization or individual.)
As you can see, while the developers of search engines like Google, Yahoo, or Bing may have good intentions to deliver the highest quality, most relevant results, that is not necessarily always what you get. Any system, no matter how good, is subject to manipulation.