How Google Search Works in 2021
Every day, billions of people come here with questions about all kinds of things. Sometimes we even get questions about Google Search itself, like how this whole thing actually works.
While this is a subject the entire book has been written about,
there is a good chance you're in the market for something a little more concise.
Google has been continuously mapping the web, hundreds of billions of pages, to create something called an
index. Think of it as the giant library we look through whenever you do search for
lasagna or anything else.
Now, the word lasagna shows up a lot on the web--pages about the history of lasagna, articles by scientists whose last name happened to be Lasagna, stuff other people might be looking for. But if you're hungry, randomly clicking through millions of links is no fun.
This is where Google's ranking algorithms come into play. First, they try to understand what you're looking for so they canbe
helpful even if you donat knows exactly the right words to use or if your spelling is a little off.
Then they sift through millions of possible matches in the index and automatically assemble a page that tries to put the most relevant information top for you to choose from. OK.
Now we have some results. But how did the algorithms actually decide what made it onto the first page?
There are hundreds of factors that go into ranking search results. So let's talk about a few
of them. You may already knowthat pages containing the words you search for are more likely to end up at the top.No surprise there. But the location of those words,
like in the page's title, or in an image's caption, those are factors, too.
There's a lot more to ranking than just words. Back when Google got started, we looked at how pages linked to each other to better understand what pages were about and how important and trustworthy they seemed.
Today,
linking is still an important factor. Another factor is location, where a search
happens. Because, if you happen to be in Ormea, Italy, you might be looking for information about their annual lasagna festival. But if you're in Omaha, Nebraska,
you probably aren't. When a web page was uploaded an important factor, too.
Pages published more recently often have more accurate information, especially in the case of a rapidly developing news story.
Of course, not every site onthe web is trying to be helpful. Just like with robocalls on your phone or spam in your email, there are a lot of sites that only exist to scam.
Every
day, scammers upload millions more of them. So just because of Instant Virus Download. netlists
the words "lasagna recipe" 400 times, that doesn't mean it's going to help you make dinner.
We spend a lot of time trying to stay one step ahead of tricks like these, making sure our algorithms can recognize scam sites and flag
them before they make it to your search results page.
Billions of times a day, whenever someone searches for
lasagna, or resume writing tips, or how to swaddle a baby, or anything else, Google
software locates all the potentially relevant results on the web, removes all the
spam, and ranks them based on hundreds of factors, like keywords, links, location,
and freshness. Good time to take a breath.
This last part is about how we make changes to Search. And it's important. Since 1998, when google went online, people seem to have found our results pretty helpful. But the web is always changing and people are always searching for new things.
In fact, one in every seven searches for something that's never been typed into the search box before by anyone ever. So we're always working on updates to Search, thousands every year.
How do we decide whether a change is making Search more helpful?
Well, one of the ways we evaluate potential updates to Searches is by asking people like you. Every day, thousands of search quality raters look at samples of Search results side by side, then give feedback about the relevance and reliability of the information.
To make sure those evaluations are consistent, the
raters follow a list of Search quality evaluator guidelines. Think of them as our publicly available guide to what makes a good result good.