QUOTE: “The preferred domain is the one that you would liked used to index your site’s pages (sometimes this is referred to as the canonical domain). Links may point to your site using both the www and non-www versions of the URL (for instance, http://www.example.com and http://example.com). The preferred domain is the version that you want used for your site in the search results.” Google, 2018
Search engines may penalize sites they discover using black or grey hat methods, either by reducing their rankings or eliminating their listings from their databases altogether. Such penalties can be applied either automatically by the search engines' algorithms, or by a manual site review. One example was the February 2006 Google removal of both BMW Germany and Ricoh Germany for use of deceptive practices.[54] Both companies, however, quickly apologized, fixed the offending pages, and were restored to Google's search engine results page.[55]

Page and Brin founded Google in 1998.[23] Google attracted a loyal following among the growing number of Internet users, who liked its simple design.[24] Off-page factors (such as PageRank and hyperlink analysis) were considered as well as on-page factors (such as keyword frequency, meta tags, headings, links and site structure) to enable Google to avoid the kind of manipulation seen in search engines that only considered on-page factors for their rankings. Although PageRank was more difficult to game, webmasters had already developed link building tools and schemes to influence the Inktomi search engine, and these methods proved similarly applicable to gaming PageRank. Many sites focused on exchanging, buying, and selling links, often on a massive scale. Some of these schemes, or link farms, involved the creation of thousands of sites for the sole purpose of link spamming.[25]

QUOTE: “Anytime you do a bigger change on your website if you redirect a lot of URLs or if you go from one domain to another or if you change your site’s structure then all of that does take time for things to settle down so we can follow that pretty quickly we can definitely forward the signals there but that doesn’t mean that’ll happen from one day to next” John Mueller, Google 2016
This broken-link checker makes it easy for a publisher or editor to make corrections before a page is live. Think about a site like Wikipedia, for example. The Wikipedia page for the term "marketing" contains a whopping 711 links. Not only was Check My Links able to detect this number in a matter of seconds, but it also found (and highlighted) seven broken links.