Link building is the process of generating backlinks to a website through various methods.

By obtaining more and higher trusted links thank competitors, Google evaluates a site as a higher quality website than theirs, if content and user-experience are of comparable quality. Therefore, sites with more top trusted backlinks tend to earn more top rankings in Google organic search results.

These link building methods are sometimes referred to as a range from "white hat" (very natural appearing links) to "black hat" (very automated, spammy backlinks set).

Many SEOs believe that the age of automated blackhat link building is over, which is part of the "Penguin Shock" effect.

Other SEOs believe that any undertaking to generate backlinks to a website is considered a violation of the Google webmaster guidelines.

Other SEOs at the same time disregard the Google webmaster guidelines knowingly and willingly and consider the risk of hitting a Google Penalty (of Google Algorithmic Filter) as part of their business risk. Sometimes this is referred to as "grey hat link building."

Some general types of link building are

• Link Buying (Paid Links are still a very dominant SEO strategy in some industries)
• Link Earning ("Write good content and hope that others link to it")
• Link Outreach ("Contact webmasters and other parties, asked them to link to your content")