Embedded content linking. This is most often done with either iframes or framesets — and most companies do not allow their content to be framed in such a way that it looks like someone else owns the content. If you're going to do that, you should be very aware that this annoys people. Furthermore, if you're not willing to remove the content in an iframe or the frameset around the linked page, you may be risking a lawsuit.
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.

i have never read an informative post until i came across this and am hooked. Helped me recognize broken links that i had no idea where sitting there. Also right in the beginning about having link worthy site, its like you were talking to me about writing see the link "here" and the LSI was a good tip i knew nothing about. Thank you so much and all the best.

When would this be useful? If your site has a blog with public commenting turned on, links within those comments could pass your reputation to pages that you may not be comfortable vouching for. Blog comment areas on pages are highly susceptible to comment spam. Nofollowing these user-added links ensures that you're not giving your page's hard-earned reputation to a spammy site.
Paid search results are those in the top and bottom of the results page, indicated by the small “ad” icon. These are placements that businesses pay for to show up when users search specific keywords. Google Ads can be a very effective way of utilizing ad spend for those who are new or struggling to compete against businesses that rank higher in organic search results. It’s also great for businesses targeting keywords with high revenue potential.