Link building is a art, and most probably the hardest job that a SEO consultant has to do. Once upon a time, search engine algorithms judged a websites worth by the number of links that pointed towards it. But black hat SEOs began to take advantage of that by creating low value links. Search engines caught on to the manipulation and tried to stop it by penalizing sites using bad links. But despite that, links still remain a very important factor in determining the ranking of a website.
Search engine algorithms use links to determine the popularity, trustworthiness and authority of a website. Trusted sites often have backlinks from other trusted sites, which is good for both sites in the long run. If links anchored with the right keywords point to a site, it is very likely that the site will achieve a high ranking. Same goes for links received from well trusted domains like government websites, universities etc.
Basics of link building
Natural search engine optimization includes building links. However, most organic links are naturally given by other websites that want to link your company or the content. There is not much that a SEO company can do to generate these high value links. Your website will need very high value, well written quality content and new content should be added periodically so that you keep getting more of those important links.
Link building through outreach comes under natural search engine optimization strategies. This is where SEO experts show their expertise. They email bloggers, reach out to sites related to yours and explain to them why creating the link will be useful for them. For example, if you sell t-shirts online, then it makes sense that a blog about apparel might create a link with your website.
Self created links are a little controversial, black hat SEOs have used every tool in their arsenal to create as many links as they can, which is why self created links are quite a taboo for search engines. Link spamming by posting on comment section in blogs, guest posts and such can be heavily penalized.