Site owners can specify if an individual link passes link equity or not. A no follow link does not pass link equity – colloquially called “link juice” – to the linking domain, while a follow link does. While followed backlinks are much more desirable, no follow links from high-quality websites can still be beneficial to enhance your brand.
(Interestingly, local SEO strategy views follow and no follow links from relevant, localized websites as equally valuable.)
Backlinks obtained from linking domains of high authority usually offer more value (link equity) than links from low-quality, new, or spammy websites. Backlinks from spammy websites should be avoided whenever possible.
Google knows if a backlink is irrelevant. If a gluten-free bakery in California links to your brick-and-mortar hiking gear shop in Colorado, the backlink is not extremely relevant and will likely not pass as much link juice as the backlink received from the mountain climbing site.
Website architecture is significant to Google, as is the positioning of a link on the page. For example, a backlink tucked in the footer of a page may not pass as much equity as one added in a relevant blog post paragraph.
A backlink listed among hundreds or thousands of links on a single page is likely not as valuable as a link referenced among fewer. Beyond link equity, a user would be hard-pressed to locate your link among the hundreds and click through to your content, eliminating value.