The following are explanations of five link classifications. They range in order from formational to naturally generated links and encompass the maturation process of a Web site. A Web site continuously acquires links throughout its lifespan and needs to secure different types of links as it grows. Link tiers indicate the next level of links needed to thrive in  the maturation process in regard to authority and link popularity. No link tier should be viewed as separate from or greater than any other classification, as tactics tend to overlap and aid Web sites in different ways.

Brokered Links are secured through negotiation or agreement and can often produce moderate to high authority links.  Brokered links often come about as a result of direct analysis of opportunities found through backlink research. They can involve a good deal of individual negotiation and must be addressed on a site by site basis, which may be time consuming.
Many brokered link opportunities are bartered arrangements between sites that, if done correctly, can elevate a site out of obscurity.

The more controversial side of the brokered link tier is link buying. Several services offer bulk link placement as a method to increase the number of search-friendly backlinks for specific keywords. Google does penalize for explicit link buys, and the risk associated with this tactic is significant. If one is looking to attempt link buying, it is best to do so sparingly and slowly. Link buys boost search visibility in the short-term but will require the use of other tactics to sustain ranking.

Community Links reflect much of the Web 2.0 landscape, referring to blogs, social media, and user generated media. These links may be gained by engaging participants in the community on their terms through link bait, relevant content and social opportunity. These links can snowball if done correctly, generating a nature stream of backlinks.  Tactics such as link baiting may result in a traffic spike that raises the search visibility of a page, but direct community involvement can foster long-term benefits.

Formational Links are the initial set of links one should pursue in establishing a new Web site.These links are sometimes overlooked during site launch and can be addressed up until the point that a Web site achieves a moderate level of backlinks or measured trust. This is subjective to the site and must be judged by the type and quality of  backlinks observed. Formational links include links from directories, easily placed links and relevant niche links.

Authoritative Links are high value inbound links from trusted online sources. These sites have high trust metrics and transfer the most link popularity per link.  Authoritative sites include trusted news sites, .edu pages, and other sites regarded highly by search engines. A site should examine its backlinks and existing offline relationships to determine any opportunity for high quality linking. While these links are the most likely to remain active, the one downside of authoritative links is that they commonly link to the domain of the target site and not individual pages. The effects of this may be balanced by savvy internal linking.

Naturally Generated Links refers to any links secured without direct pursuit. In reference to link building, these links can be news articles referring to the target site, scrapers of quality “nofollow sites such as Wikipedia, links from press release circulation and links for sites monitoring RSS feeds. Naturally generated links are the end goal of a link development
campaign as they reflect continued link stability. A healthy influx of naturally generated links will help keep a Web site fresh and competitive indefinitely. Link seeding strategies are needed to make this link tier effective for client campaigns.