SEO may generate an adequate return on investment. However, search engines are not paid for organic search traffic, their algorithms change, and there are no guarantees of continued referrals. Due to this lack of guarantees and certainty, a business that relies heavily on search engine traffic can suffer major losses if the search engines stop sending visitors.[61] Search engines can change their algorithms, impacting a website's placement, possibly resulting in a serious loss of traffic. According to Google's CEO, Eric Schmidt, in 2010, Google made over 500 algorithm changes – almost 1.5 per day.[62] It is considered a wise business practice for website operators to liberate themselves from dependence on search engine traffic.[63] In addition to accessibility in terms of web crawlers (addressed above), user web accessibility has become increasingly important for SEO.

To this end, companies make use of platforms such as Facebook, Twitter, YouTube, and Instagram to reach audiences much wider than through the use of traditional print/TV/radio advertisements alone at a fraction of the cost, as most social networking sites can be used at little or no cost (however, some websites charge companies for premium services). This has changed the ways that companies approach to interact with customers, as a substantial percentage of consumer interactions are now being carried out over online platforms with much higher visibility. Customers can now post reviews of products and services, rate customer service, and ask questions or voice concerns directly to companies through social media platforms. According to Measuring Success, over 80% of consumers use the web to research products and services.[30] Thus social media marketing is also used by businesses in order to build relationships of trust with consumers.[31] To this aim, companies may also hire personnel to specifically handle these social media interactions, who usually report under the title of Online community managers. Handling these interactions in a satisfactory manner can result in an increase of consumer trust. To both this aim and to fix the public's perception of a company, 3 steps are taken in order to address consumer concerns, identifying the extent of the social chatter, engaging the influencers to help, and developing a proportional response.[32]

LinkedIn, a professional business-related networking site, allows companies to create professional profiles for themselves as well as their business to network and meet others.[41] Through the use of widgets, members can promote their various social networking activities, such as Twitter stream or blog entries of their product pages, onto their LinkedIn profile page.[42] LinkedIn provides its members the opportunity to generate sales leads and business partners.[43] Members can use "Company Pages" similar to Facebook pages to create an area that will allow business owners to promote their products or services and be able to interact with their customers.[44] Due to spread of spam mail sent to job seeker, leading companies prefer to use LinkedIn for employee's recruitment instead using different a job portal. Additionally, companies have voiced a preference for the amount of information that can be gleaned from a LinkedIn profile, versus a limited email.[45]
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.
Webmasters and content providers began optimizing websites for search engines in the mid-1990s, as the first search engines were cataloging the early Web. Initially, all webmasters only needed to submit the address of a page, or URL, to the various engines which would send a "spider" to "crawl" that page, extract links to other pages from it, and return information found on the page to be indexed.[5] The process involves a search engine spider downloading a page and storing it on the search engine's own server. A second program, known as an indexer, extracts information about the page, such as the words it contains, where they are located, and any weight for specific words, as well as all links the page contains. All of this information is then placed into a scheduler for crawling at a later date.
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