The term "hyperlink" was coined in 1965 (or possibly 1964) by Ted Nelson at the start of Project Xanadu. Nelson had been inspired by "As We May Think", a popular 1945 essay by Vannevar Bush. In the essay, Bush described a microfilm-based machine (the Memex) in which one could link any two pages of information into a "trail" of related information, and then scroll back and forth among pages in a trail as if they were on a single microfilm reel.
Robots.txt is not an appropriate or effective way of blocking sensitive or confidential material. It only instructs well-behaved crawlers that the pages are not for them, but it does not prevent your server from delivering those pages to a browser that requests them. One reason is that search engines could still reference the URLs you block (showing just the URL, no title or snippet) if there happen to be links to those URLs somewhere on the Internet (like referrer logs). Also, non-compliant or rogue search engines that don't acknowledge the Robots Exclusion Standard could disobey the instructions of your robots.txt. Finally, a curious user could examine the directories or subdirectories in your robots.txt file and guess the URL of the content that you don't want seen.
The W3C Recommendation called XLink describes hyperlinks that offer a far greater degree of functionality than those offered in HTML. These extended links can be multidirectional, linking from, within, and between XML documents. It can also describe simple links, which are unidirectional and therefore offer no more functionality than hyperlinks in HTML.
Organic search results are free and display below Google Ads and sometimes local results. Google uses a sophisticated algorithm to determine which sites rank highest for organic search results based on keyword usage, relevance, site design, and other factors. Generally, Google provides the highest quality, most relevant results based on the keyword(s) used by the searcher.