Search engine optimization strategies come in many flavors: organic, paid, negative, questionable, dubious, unethical, and downright illegal. With every update and amendment to the Google search engine algorithm, SEO professionals will try to push the boundaries of their craft in order to boost the ranking of their clients without running afoul of the algorithm guidelines and signals, which could lead to penalties in the forms of reduced ranking.
One particular tactic that some SEO practitioners have found effective is centered on the content found in archived websites such as the ones hosted at the Wayback Machine, also known as the Internet Archive; these sites are no longer indexed and ranked by the Google crawlers, but they often hold content that made them popular when they were still active. There is not much that the managers of the Internet Archive can do about scraping this content and finding a new purpose for it; some SEO agencies have achieved considerable success doing this, and there are cases in which the content is even syndicated in the form of guest posts.
Since the Wayback Machine is not within the purview of Google, there is no significant risk of incurring into a duplication penalty with archived content. The problem with this tactic, which certainly should be filed under the black hat category, is that the content being scraped is copyrighted. Using archived content without permission can actually result in a civil lawsuit or at least a take down notice under the provisions of the Digital Millennium Copyright Act. Once a DMCA notice is filed, you can kiss all your SEO efforts goodbye.
The right way of breathing new life into an old website is to legally purchase it, apply on-page SEO work that is in line with the current algorithm, and take the organic steps to boost rank. It is always easier to purchase everything from the domain to the content, but this may not always be possible. If the archived material is inspiring, a more affordable and legal move would be to contract a writer who can put a modern, relevant, and adequate spin on it. For more information click here https://www.reddit.com/r/SEO/comments/hebg0v/arethesetactics_acceptable/.