Backlinks from reliable and authoritative websites are significantly valuable. However, in order to benefit from the power of such backlinks, the relevant link must be marked with the "dofollow" tag. When an external link on a website is marked as "dofollow", it means that the origin site passes its authority to the destination site and Google knows about it. Therefore, webmasters should regularly keep tabs on the external links and the links that have the dofollow tag on their websites. Links to untrustworthy websites should be marked with the nofollow tag.