What is Link Hoarding?
Link hoarding - aka PageRank hoarding - in SEO refers to the practice of acquiring and accumulating a large number of inbound links to a website while refraining from giving outbound links.
The belief behind this practice is that outbound links can drain the website's page rank and that acquiring as many inbound links as possible will maximize the website's search engine ranking.
While inbound backlinks are important for a website's search engine ranking, having no outbound links may indicate that the website is not interested in participating in the wider online community.
This can be seen as a grey-hat SEO practice, as it is not explicitly prohibited by search engines, but it can be viewed as manipulative.
How does link hoarding work?
Link hoarding works by artificially manipulating a website's inbound and outbound links in order to increase its link equity, which refers to the value and authority a website gains from other websites linking to it.
Link equity is an important factor in search engine rankings, as it helps search engines determine the relevance and quality of a website.
Webmasters who engage in link hoarding attempt to maximize the amount of link equity flowing into their website while minimizing the amount of link equity flowing out of their website.
This is typically done by using various techniques such as buying or exchanging links, participating in link farms or link exchanges, or using automated programs to generate backlinks.
The goal of link hoarding is to create an artificially high link equity score, which can improve a website's search engine rankings.
However, search engines have become increasingly sophisticated at detecting manipulative practices such as link hoarding, and may catch websites that engage in these practices.
Is link hoarding a bad practice?
Link hoarding is generally considered a bad practice in the world of search engine optimization.
It involves manipulating a website's link equity by artificially increasing the number of inbound links while minimizing the number of outbound links.
This can be seen as unethical, as it attempts to artificially inflate the website's search engine rankings without providing any real value to users.
Furthermore, link hoarding can harm a website's credibility and reputation, as visitors may view it as self-promoting and unhelpful.
By contrast, ethical and sustainable SEO practices such as building high-quality, relevant links that provide value to users can improve a website's search engine rankings and create a more valuable and engaging online presence.
Are nofollow outbound links considered link hoarding?
No, nofollow outbound links are not considered link hoarding. Nofollow outbound links are hyperlinks that contain a rel="nofollow" attribute in the HTML code, indicating to search engine crawlers that the link should not be used for the purposes of ranking a website in search results.
John Mueller clears this up this way:

While nofollow links may not provide direct SEO benefits, they can still be valuable for providing additional context, sources, or references to a piece of content.
However, minimizing the outwards flow of equity using nofollow and maximizing inbound links will be taken as hoarding.
Can one gain equity without hoarding links?
Gaining link equity is an essential aspect of search engine optimization, but it's important to do it in a natural and ethical way.
While link hoarding can be seen as manipulative, there are many other ways to gain link equity.
One effective way is to focus on creating high-quality, relevant content that is useful and engaging for users.
By doing this, people are more likely to share your content and link to it on their own websites.
Building relationships with other website owners in your niche or industry is also a great way to gain valuable links and exposure to new audiences.
Additionally, participating in online communities and forums, as well as providing valuable resources and tools on your website, are also effective ways to gain natural link equity.
Adopting such ethical methods to gain link equity can help website owners enhance their search engine rankings and establish a more valuable and sustainable online presence.
Conclusion
Link hoarding is a manipulative practice that involves artificially manipulating a website's link equity in an attempt to improve its search engine rankings.
While it may produce short-term gains, link hoarding will be seen as an unethical practice. Instead of relying on unethical practices, website owners should focus on building high-quality, relevant links that provide value to their audience.