Tiered link building uses two levels of backlinks to boost your site’s...

https://www.bookmark-friend.win/tiered-link-building-uses-two-levels-of-links-to-boost-your-website-s-seo-tier

Tiered link building uses two levels of backlinks to boost your site’s authority. Tier 1 links point directly to your site, while Tier 2 links support those Tier 1 backlinks