What is link building?

Link building is a concept that is part of the topic of OffPage Optimization and describes the process of gaining external links (also called backlinks). The goal of link building is to intentionally increase the amount of quality backlinks which point to your own website. Link building can be done by conventional strategies, or more creative means.

Why are backlinks important?

Backlinks represent a reference from one website [A] to another website [B]. Searchengines interpret a backlink as a recommendation. In this example, website [A] recommends website [B]. This recommendation is a significant signal for searchengines to evaluate the relevancy of a website on a specific subject.

Domain Popularity is a strongly weighted factor in the Google Ranking Factors.

You can get a detailed evaluation of the backlink profile of any domain you like, as a whole or for specific details, in the link-module of the SISTRIX Toolbox:

Domain information overview page in the SISTRIX Toolbox
Link building: Overview of the backlink data of the domain zappos.com

Video explanation by Matt Cutts on the subject of link building