The priority given to the placement of a link on the results page of a Web search. For example, Google's PageRank system, named after co-founder Larry Page, classifies a site based on the number of links that point to it from other sites (the "backlinks"). The concept is that if very prominent sites link to a site, the site has greater value. The more popular the backlink sites themselves are, the higher the ranking as well.
Search Results: Ordered by relevance to your query, with the result that Google considers the most relevant listed first. Consequently you are likely to find what you’re seeking quickly by looking at the results in the order in which they appear. Google assesses relevance by considering over a hundred factors, including how many other pages link to the page, the positions of the search terms within the page, and the proximity of the search terms to one another.

Facebook Ads, which has an unparalleled targeting system (and also allows you to advertise on Instagram). Facebook Ads has two main strengths: retargeting based on segmented marketing and custom audiences and the ability to introduce your brand to customers who didn’t know they wanted it. Google AdWords is all about demand harvesting, while Facebook Ads is all about demand generation.
Black hat SEO attempts to improve rankings in ways that are disapproved of by the search engines, or involve deception. One black hat technique uses text that is hidden, either as text colored similar to the background, in an invisible div, or positioned off screen. Another method gives a different page depending on whether the page is being requested by a human visitor or a search engine, a technique known as cloaking. Another category sometimes used is grey hat SEO. This is in between black hat and white hat approaches, where the methods employed avoid the site being penalized, but do not act in producing the best content for users. Grey hat SEO is entirely focused on improving search engine rankings.

Say you're running a PPC ad for the keyword "Nikon D90 digital camera" -- a product you sell on your website. You set up the ad to run whenever this keyword is searched for on your chosen engine, and you use a URL that redirects readers who click on your ad to your site's home page. Now, this user must painstakingly click through your website's navigation to find this exact camera model -- if he or she even bothers to stick around.

If you have the Google toolbar installed in your browser, you will be used to seeing each page’s PageRank as you browse the web. But all isn’t always as it seems. Many pages that Google displays the PageRank for haven’t been indexed in Google and certainly don’t have any PageRank in their own right. What is happening is that one or more pages on the site have been indexed and a PageRank has been calculated. The PageRank figure for the site’s pages that haven’t been indexed is allocated on the fly – just for your toolbar. The PageRank itself doesn’t exist.

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]