1. To discover new web pages
2. To help determine how well a page should rank in their results

Once search engines have crawled pages on the web, they can extract the content of those pages and add it to their indexes. In this way, they can decide if they feel a page is of sufficient quality to be ranked well for relevant keywords (Google created a short video to explain that process). When they are deciding this, the search engines do not just look at the content of the page; they also look at the number of links pointing to that page from external websites and the quality of those external websites. Generally speaking, the more high-quality websites that link to you, the more likely you are to rank well in search results.

Links as a ranking factor are what allowed Google to start to dominate the search engine market back in the late 1990s. One of Google's founders, Larry Page, invented PageRank, which Google used to measure the quality of a page based in part on the number of links pointing to it. This metric was then used as part of the overall ranking algorithm and became a strong signal because it was a very good way of determining the quality of a page.

It was so effective because it was based upon the idea that a link could be seen as a vote of confidence about a page, i.e., it wouldn't get links if it didn't deserve to. The theory is that when someone links to another website, they are effectively saying it is a good resource. Otherwise, they wouldn't link to it, much in the same way that you wouldn't send a friend to a bad restaurant.

Link building is the process of acquiring hyperlinks from other websites to your own. A hyperlink (usually just called a link) is a way for users to navigate between pages on the internet. Search engines use links to crawl the web; they will crawl the links between the individual pages on your website, and they will crawl the links between entire websites. There are many techniques for building links, and while they vary in difficulty, SEOs tend to agree that link building is one of the hardest parts of their jobs. Many SEOs spend the majority of their time trying to do it well. For that reason, if you can master the art of building high-quality links, it can truly put you ahead of both other SEOs and your competition.

Why is link building important for SEO?

The anatomy of a hyperlink

In order to understand the importance of link building, it's important to first understand the basics of how a link is created, how the search engines see links, and what they can interpret from them.

What Is Link Building & Why Is It Important?

Whether you're brand new to link building or have been doing it for a while, we're sure you'll find something useful in this guide. The landscape of SEO and link building is always changing, and today, the importance of building high-quality links has never been higher. The need to understand and implement high-quality campaigns is essential if you're going to compete and thrive online, and that isn't going to change any time soon. This guide is designed to get you going quickly and in the right direction. There is a lot to take in, but we've broken everything up into easy-to-digest chapters and have included lots of examples along the way. We hope you enjoy The Beginner's Guide to Link Building.

If you are serious about improving search traffic and are unfamiliar with SEO, we recommend reading this guide front-to-back. It's short and easy to understand. There's a printable PDF version for those who'd prefer, and dozens of linked-to resources on other sites and pages that are worthy of your attention. Because you've given us your attention, we've attempted to remain faithful to Mr. William Strunk's famous quote:


"A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts."

Every section of this guide is critical to understanding the most effective practices of search engine optimization.

The world of SEO is complex, but most people can easily understand the basics. Even a small amount of knowledge can make a big difference. For the most part, SEO education is free and available on the web, including guides like this. Combine this with a little practice and you are well on your way to becoming a guru.
Depending on your time commitment, willingness to learn, and complexity of your website(s), you may decide you need an expert to handle things for you. Firms that practice SEO can vary; some have a highly specialized focus, while others take a more broad and general approach. Optimizing a web site for search engines can require looking at so many unique elements that many practitioners of SEO (SEOs) consider themselves to be in the broad field of optimization and website strategy.
Still, even in this case, it's good to have a firm grasp of the core concepts.

Search engines are smart, but they still need help. The major engines are always working towards improving their technology to crawl the web more deeply and return better results to users. However, there is a limit to how search engines can operate. Whereas the right SEO can net you thousands of visitors and attention, the wrong moves can hide or bury your site deep in the search results where visibility is minimal.
In addition to making content available to search engines, SEO also helps boost rankings so that content will be placed where searchers will more readily find it. The Internet is becoming increasingly competitive, and those companies who perform SEO will have a decided advantage in visitors and customers.