For search engines that crawl the vast metropolis of the web, links are the streets between pages. Since the late 1990s search engines have treated links as votes for popularity and importance in the ongoing democratic opinion poll of the web. The engines themselves have refined the use of link data to a fine art, and use complex algorithms to perform nuanced evaluations of sites and pages based on this information. Through links, engines can not only analyze the popularity websites and pages based on the number and popularity of pages linking to them, but also metrics like trust, spam, and authority. Trustworthy sites tend to link to other trusted sites, while spammy sites receive very few links from trusted sources. Link building is an art. It's almost always the most challenging part of an SEO's job, but also the one most critical to success. Link building requires creativity, hustle, and often, a budget. No two link building campaigns are the same, and the way you choose to build links depends as much upon your website as it does your personality.
How do search engines assign value to links? To answer this, we need to explore the individual elements of a link, and look at how the search engines assess these elements. We don't fully understand the proprietary metrics that search engines use, but through analysis of patent applications, years of experience, and hands-on testing, we can draw some intelligent assumptions that hold up in the real world. Below is a list of notable factors worthy of consideration. These signals, and many more, are considered by professional SEOs when measuring link value and a site's link profile.
The link building activities you engage in depend largely on the type of site you're working with. For smaller sites, manual link building, including directories, link requests, and link exchanges may be a part of the equation. With larger sites, these tactics tend to fall flat and more scalable solutions are required. Search for sites like yours by using keywords and phrases directly relevant to your business. When you locate sites that aren't directly competitive, email them, use their online forms, call them on the phone, or even send them a letter by mail to start a conversation about getting a link.