QUOTE:  Each piece of duplication in your on-page SEO strategy is ***at best*** wasted opportunity. Worse yet, if you are aggressive with aligning your on page heading, your page title, and your internal + external link anchor text the page becomes more likely to get filtered out of the search results (which is quite common in some aggressive spaces). Aaron Wall, 2009

QUOTE: “Google Webmaster Tools notice of detected doorway pages on xxxxxxxx – Dear site owner or webmaster of xxxxxxxx, We’ve detected that some of your site’s pages may be using techniques that are outside Google’s Webmaster Guidelines. Specifically, your site may have what we consider to be doorway pages – groups of “cookie cutter” or low-quality pages. Such pages are often of low value to users and are often optimized for single words or phrases in order to channel users to a single location. We believe that doorway pages typically create a frustrating user experience, and we encourage you to correct or remove any pages that violate our quality guidelines. Once you’ve made these changes, please submit your site for reconsideration in Google’s search results. If you have any questions about how to resolve this issue, please see our Webmaster Help Forum for support.” Google Search Quality Team
QUOTE: “The preferred domain is the one that you would liked used to index your site’s pages (sometimes this is referred to as the canonical domain). Links may point to your site using both the www and non-www versions of the URL (for instance, http://www.example.com and http://example.com). The preferred domain is the version that you want used for your site in the search results.” Google, 2018
The last time I looked Google displayed as many characters as it can fit into a block element that’s about 600px wide and doesn’t exceed 1 line of text (on desktop). So – THERE IS NO BEST PRACTICE AMOUNT OF CHARACTERS any SEO could lay down as exact best practice to GUARANTEE a title will display, in full in Google, at least, as the search snippet title, on every device. Ultimately – only the characters and words you use will determine if your entire page title will be seen in a Google search snippet.
The leading search engines, such as Google, Bing and Yahoo!, use crawlers to find pages for their algorithmic search results. Pages that are linked from other search engine indexed pages do not need to be submitted because they are found automatically. The Yahoo! Directory and DMOZ, two major directories which closed in 2014 and 2017 respectively, both required manual submission and human editorial review.[40] Google offers Google Search Console, for which an XML Sitemap feed can be created and submitted for free to ensure that all pages are found, especially pages that are not discoverable by automatically following links[41] in addition to their URL submission console.[42] Yahoo! formerly operated a paid submission service that guaranteed crawling for a cost per click;[43] however, this practice was discontinued in 2009.
In addition to processing the text content on your web pages, Google will also try to figure out what your images are about as well. Alt Text is a short description that you can customize for each image to let Google know what the image is about. Setting short, descriptive Alt Texts through our site builder will help Google better associate your web pages with the search terms you're trying to target.
A satisfying UX is can help your rankings, with second-order factors taken into consideration. A poor UX can seriously impact your human-reviewed rating, at least. Google’s punishing algorithms probably class pages as something akin to a poor UX if they meet certain detectable criteria e.g. lack of reputation or old-school SEO stuff like keyword stuffing a site.
QUOTE: “To summarize, a lack of helpful SC may be a reason for a Low quality rating, depending on the purpose of the page and the type of website. We have different standards for small websites which exist to serve their communities versus large websites with a large volume of webpages and content. For some types of “webpages,” such as PDFs and JPEG files, we expect no SC at all.” Google Search Quality Evaluator Guidelines 2017
QUOTE: “I think there is probably a misunderstanding that there’s this one site-wide number that Google keeps for all websites and that’s not the case.  We look at lots of different factors and there’s not just this one site-wide quality score that we look at. So we try to look at a variety of different signals that come together, some of them are per page, some of them are more per site, but it’s not the case where there’s one number and it comes from these five pages on your website.” John Mueller, Google
Google expects pages to “be edited, reviewed, and updated on a regular basis” especially if they are for important issues like medical information, and states not all pages are held to such standards, but one can expect that Google wants information updated in a reasonable timescale. How reasonable this is, is dependant on the TOPIC and the PURPOSE of the web page RELATIVE to competing pages on the web.
If you are improving user experience by focusing primarily on the quality of the MC of your pages and avoiding – even removing – old-school SEO techniques – those certainly are positive steps to getting more traffic from Google in 2019 – and the type of content performance Google rewards is in the end largely at least about a satisfying user experience.
One common scam is the creation of "shadow" domains that funnel users to a site by using deceptive redirects. These shadow domains often will be owned by the SEO who claims to be working on a client's behalf. However, if the relationship sours, the SEO may point the domain to a different site, or even to a competitor's domain. If that happens, the client has paid to develop a competing site owned entirely by the SEO.
QUOTE: “Duplicated content is often not manipulative and is commonplace on many websites and often free from malicious intent. Copied content can often be penalised algorithmically or manually. Duplicate content is not penalised, but this is often not an optimal set-up for pages, either. Be VERY careful ‘spinning’ ‘copied’ text to make it unique!” Shaun Anderson, Hobo, 2018
At Yoast, we practice what we call ‘holistic SEO‘. This means that your primary goal should be to build and maintain the best possible website. Don’t try to fool Google, but use a sustainable long-term strategy. Ranking will come automatically if your website is of extremely high quality. Google wants to get its users to the right place, as its mission is to index all the world’s online information and make it universally accessible and useful.