If content is king, then backlinks are deities.
At least according to search engines. Although content is more important than ever for search engine optimization, building the right profile of backlinks is essential to increasing your website’s authority for particular keywords, which in turn helps boost organic rankings. An infographic prepared by Vertical Measures illustrates the effect of different types of links one can build, such as organic valuable links, nofollow links (which are useless for SEO efforts) and paid links, which can result in harsh penalties handed down by Google or Bing. Backlinks also need to be analyzed from a technical level to make sure authority is passed over: for example, a 301 redirect can result in a link’s value being slightly affected, whereas a backlink to a broken web page (404 error) can result in no value being passed over whatsoever.
This guide can become handy when evaluating your site’s backlink strategy, particularly if it you see an an abundance of 404 errors in webmaster reports. Effective search engine optimization campaigns require a strategic link building strategy, but numerous resources can be wasted if they are not created properly (for example, having a link back to your site coded with a nofollow tag).