Early versions of search algorithms relied on webmaster-provided information such as the keyword meta tag or index files in engines like ALIWEB. Meta tags provide a guide to each page's content. Using metadata to index pages was found to be less than reliable, however, because the webmaster's choice of keywords in the meta tag could potentially be an inaccurate representation of the site's actual content. Inaccurate, incomplete, and inconsistent data in meta tags could and did cause pages to rank for irrelevant searches.[10][dubious – discuss] Web content providers also manipulated some attributes within the HTML source of a page in an attempt to rank well in search engines.[11] By 1997, search engine designers recognized that webmasters were making efforts to rank well in their search engine, and that some webmasters were even manipulating their rankings in search results by stuffing pages with excessive or irrelevant keywords. Early search engines, such as Altavista and Infoseek, adjusted their algorithms to prevent webmasters from manipulating rankings.[12]

Google's search engine marketing is one of the western world's marketing leaders, while its search engine marketing is its biggest source of profit.[17] Google's search engine providers are clearly ahead of the Yahoo and Bing network. The display of unknown search results is free, while advertisers are willing to pay for each click of the ad in the sponsored search results.

Social media marketing, or SMM, is a form of internet marketing that involves creating and sharing content on social media networks in order to achieve your marketing and branding goals. Social media marketing includes activities like posting text and image updates, videos, and and other content that drives audience engagement, as well as paid social media advertising.

Another example when the “nofollow" attribute can come handy are widget links. If you are using a third party's widget to enrich the experience of your site and engage users, check if it contains any links that you did not intend to place on your site along with the widget. Some widgets may add links to your site which are not your editorial choice and contain anchor text that you as a webmaster may not control. If removing such unwanted links from the widget is not possible, you can always disable them with “nofollow" attribute. If you create a widget for functionality or content that you provide, make sure to include the nofollow on links in the default code snippet.

Many blogging software packages automatically nofollow user comments, but those that don't can most likely be manually edited to do this. This advice also goes for other areas of your site that may involve user-generated content, such as guest books, forums, shout-boards, referrer listings, etc. If you're willing to vouch for links added by third parties (for example, if a commenter is trusted on your site), then there's no need to use nofollow on links; however, linking to sites that Google considers spammy can affect the reputation of your own site. The Webmaster Help Center has more tips on avoiding comment spam40, for example by using CAPTCHAs and turning on comment moderation.
On April 24, 2012 many started to see that Google has started to penalize companies that are buying links for the purpose of passing off the rank. The Google Update was called Penguin. Since then, there have been several different Penguin/Panda updates rolled out by Google. SEM has, however, nothing to do with link buying and focuses on organic SEO and PPC management. As of October 20, 2014 Google has released three official revisions of their Penguin Update.

In 2012 during Hurricane Sandy, Gap sent out a tweet to its followers telling them to stay safe but encouraged them to shop online and offered free shipping. The tweet was deemed insensitive, and Gap eventually took it down and apologized.[96] Numerous additional online marketing mishap examples exist. Examples include a YouTube video of a Domino's Pizza employee violating health code standards, which went viral on the Internet and later resulted in felony charges against two employees.[93][97] A Twitter hashtag posted by McDonald's in 2012 attracting attention due to numerous complaints and negative events customers experienced at the chain store; and a 2011 tweet posted by a Chrysler Group employee that no one in Detroit knows how to drive.[98] When the Link REIT opened a Facebook page to recommend old-style restaurants, the page was flooded by furious comments criticizing the REIT for having forced a lot of restaurants and stores to shut down; it had to terminate its campaign early amid further deterioration of its corporate image.[99]

Website saturation and popularity, or how much presence a website has on search engines, can be analyzed through the number of pages of the site that are indexed by search engines (saturation) and how many backlinks the site has (popularity). It requires pages to contain keywords people are looking for and ensure that they rank high enough in search engine rankings. Most search engines include some form of link popularity in their ranking algorithms. The following are major tools measuring various aspects of saturation and link popularity: Link Popularity, Top 10 Google Analysis, and Marketleap's Link Popularity and Search Engine Saturation.
Optimizing a website may involve editing its content, adding content, modifying HTML, and associated coding to both increase its relevance to specific keywords and to remove barriers to the indexing activities of search engines.[citation needed] 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.[3]