QUOTE: “Over time, we’ve seen sites try to maximize their “search footprint” without adding clear, unique value. These doorway campaigns manifest themselves as pages on a site, as a number of domains, or a combination thereof. To improve the quality of search results for our users, we’ll soon launch a ranking adjustment to better address these types of pages. Sites with large and well-established doorway campaigns might see a broad impact from this change.” Google 2015
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 added one keyword to the page in plain text because adding the actual ‘keyword phrase’ itself would have made my text read a bit keyword stuffed for other variations of the main term. It gets interesting if you do that to a lot of pages, and a lot of keyword phrases. The important thing is keyword research – and knowing which unique keywords to add.
SEO is also about making your search engine result relevant to the user's search query so more people click the result when it is shown in search. In this process, snippets of text and meta data are optimized to ensure your snippet of information is appealing in the context of the search query to obtain a high CTR (click through rate) from search results.
Provide full functionality on all devices. Mobile users expect the same functionality - such as commenting and check-out - and content on mobile as well as on all other devices that your website supports. In addition to textual content, make sure that all important images and videos are embedded and accessible on mobile devices. For search engines, provide all structured data and other metadata - such as titles, descriptions, link-elements, and other meta-tags - on all versions of the pages.
Google recommends that all websites use https:// when possible. The hostname is where your website is hosted, commonly using the same domain name that you'd use for email. Google differentiates between the "www" and "non-www" version (for example, "www.example.com" or just "example.com"). When adding your website to Search Console, we recommend adding both http:// and https:// versions, as well as the "www" and "non-www" versions.