When you enter a search query into your favorite search engine, it instantly returns a list of Web content results that semantically match your keywords or key phrases. These are then sorted and presented in order of their relevance to your query. Behind the scenes, these results take a lot of processing power to compute. Search engines use a variety of different techniques to make this happen.

Search engines index billions of documents on the Internet that contain words or other elements that can be matched to your search query. The vast majority of these documents are not necessarily relevant to your search. However, a search engine may be able to identify a small set of documents that are both important and highly relevant for your query.

The goal of a search engine is to provide the user with a set of high-quality Web pages that satisfy their search query. The relevance of a given result depends on a number of different factors. These can include the keywords used in a search query and how often they appear on a given page, a page’s freshness, whether other pages link to it, the language detected (if possible), and more.

Every search engine has its own methods to interpret and process these data. The exact methods vary from one engine to the next, but most share some of the same basic principles.

For example, a search engine may look for a keyword in the title of a document, in the body of the text, and even in its meta tags or image alt attributes. It will also analyze the context in which a keyword appears to determine its meaning, as well as consider the frequency and placement of the keyword within the document’s text. A search engine will then rank the document based on these factors, as well as its popularity and authority, to present the user with the best possible matches for their query.

In addition to these standard techniques, search engines have evolved to handle a wide variety of special situations. For example, voice, local and mobile search provide nuanced opportunities for brands to reach users in new ways, and they all use some of the same fundamentals that underlie traditional search. Search engine technology is increasingly sophisticated in its attempts to discourage keyword stuffing, in which a site is deliberately stuffed with numerous unrelated keywords to artificially boost its ranking. This type of manipulation is referred to as spamdexing. The technology has also become more adept at recognizing and rewarding sites that provide rich, structured data on their pages, which is known as structured markup. This includes elements like reviews, images and videos, all of which can help a search engine better understand the context of a given query. As a result, these types of websites are often shown higher on results pages.