QUOTE: “The duration performance scores can be used in scoring resources and websites for search operations. The search operations may include scoring resources for search results, prioritizing the indexing of websites, suggesting resources or websites, protecting particular resources or websites from demotions, precluding particular resources or websites from promotions, or other appropriate search operations.” A Panda Patent on Website and Category Visit Durations

As of 2009, there are only a few large markets where Google is not the leading search engine. In most cases, when Google is not leading in a given market, it is lagging behind a local player. The most notable example markets are China, Japan, South Korea, Russia and the Czech Republic where respectively Baidu, Yahoo! Japan, Naver, Yandex and Seznam are market leaders.

Google engineers are building an AI – but it’s all based on simple human desires to make something happen or indeed to prevent something. You can work with Google engineers or against them. Engineers need to make money for Google but unfortunately for them, they need to make the best search engine in the world for us humans as part of the deal. Build a site that takes advantage of this. What is a Google engineer trying to do with an algorithm? I always remember it was an idea first before it was an algorithm. What was that idea? Think “like” a Google search engineer when making a website and give Google what it wants. What is Google trying to give its users? Align with that. What does Google not want to give its users? Don’t look anything like that. THINK LIKE A GOOGLE ENGINEER & BUILD A SITE THEY WANT TO GIVE TOP RANKINGS.
While Google never sells better ranking in our search results, several other search engines combine pay-per-click or pay-for-inclusion results with their regular web search results. Some SEOs will promise to rank you highly in search engines, but place you in the advertising section rather than in the search results. A few SEOs will even change their bid prices in real time to create the illusion that they "control" other search engines and can place themselves in the slot of their choice. This scam doesn't work with Google because our advertising is clearly labeled and separated from our search results, but be sure to ask any SEO you're considering which fees go toward permanent inclusion and which apply toward temporary advertising.
Maintenance. Ongoing addition and modification of keywords and website con­tent are necessary to continually improve search engine rankings so growth doesn’t stall or decline from neglect. You also want to review your link strategy and ensure that your inbound and outbound links are relevant to your business. A blog can provide you the necessary structure and ease of content addition that you need. Your hosting company can typically help you with the setup/installation of a blog.
Another illicit practice is to place "doorway" pages loaded with keywords on the client's site somewhere. The SEO promises this will make the page more relevant for more queries. This is inherently false since individual pages are rarely relevant for a wide range of keywords. More insidious, however, is that these doorway pages often contain hidden links to the SEO's other clients as well. Such doorway pages drain away the link popularity of a site and route it to the SEO and its other clients, which may include sites with unsavory or illegal content.
The biggest advantage any one provider has over another is experience and resource. The knowledge of what doesn’t work and what will hurt your site is often more valuable than knowing what will give you a short-lived boost. Getting to the top of Google is a relatively simple process. One that is constantly in change. Professional SEO is more a collection of skills, methods and techniques. It is more a way of doing things, than a one-size-fits-all magic trick.
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.
By relying so much on factors such as keyword density which were exclusively within a webmaster's control, early search engines suffered from abuse and ranking manipulation. To provide better results to their users, search engines had to adapt to ensure their results pages showed the most relevant search results, rather than unrelated pages stuffed with numerous keywords by unscrupulous webmasters. This meant moving away from heavy reliance on term density to a more holistic process for scoring semantic signals.[13] Since the success and popularity of a search engine is determined by its ability to produce the most relevant results to any given search, poor quality or irrelevant search results could lead users to find other search sources. Search engines responded by developing more complex ranking algorithms, taking into account additional factors that were more difficult for webmasters to manipulate. In 2005, an annual conference, AIRWeb (Adversarial Information Retrieval on the Web), was created to bring together practitioners and researchers concerned with search engine optimization and related topics.[14]
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.