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.
Have you ever received a warning from Google Chrome to not visit a page? It will block the page and prevent you from going there because of some security issue. We begin by ensuring your website passes a SSL Certificate Validity Check. This a whole range of security protocols that should be within your website’s coding or built-in to the domain. It shows the world that your site is trustworthy!
Optimizing a website may involve editing its content, adding content, and modifying HTML and associated coding to both increase its relevance to specific keywords and remove barriers to the indexing activities of search engines like Google ,Yahoo etc. Promoting a site to increase the number of backlinks, or inbound links, is another SEO tactic. By May 2015, mobile search had surpassed desktop search.