All you need to notice from this kind of articles is what I & most of the others newbies focusing on the SEO link-building. I have seen many bloggers spending time on different ways of SEO link building instead of providing the value to the content and its social promotions. You may call it ignoring the Google, but we all know that the Google bot doesn’t ignore anchored dofollow or nofollow backlinks to calculate your PageRank.
A poor 404 page and user interaction with it, can only lead to a ‘poor user experience’ signal at Google’s end, for a number of reasons. I will highlight a poor 404 page in my audits and actually programmatically look for signs of this issue when I scan a site. I don’t know if Google looks at your site that way to rate it e.g. algorithmically determines if you have a good 404 page – or if it is a UX factor, something to be taken into consideration further down the line – or purely to get you thinking about 404 pages (in general) to help prevent Google wasting resources indexing crud pages and presenting poor results to searchers. I think rather that any rating would be a second order scoring including data from user activity on the SERPs – stuff we as SEO can’t see.
QUOTE: “Returning a code other than 404 or 410 for a non-existent page (or redirecting users to another page, such as the homepage, instead of returning a 404) can be problematic. Firstly, it tells search engines that there’s a real page at that URL. As a result, that URL may be crawled and its content indexed. Because of the time Googlebot spends on non-existent pages, your unique URLs may not be discovered as quickly or visited as frequently and your site’s crawl coverage may be impacted (also, you probably don’t want your site to rank well for the search query” GOOGLE
When using the Keyword Explorer, Ahrefs will also produce the "parent topic" of the keyword you looked up, as you can see in the screenshot above, underneath the Keyword Difficulty meter. A keyword's parent topic is a broader keyword with higher search volume than your intended keyword, but likely has the same audience and ranking potential -- giving you more a valuable SEO opportunity when optimizing a particular blog post or webpage.