As marketing strategy

SEO is not an appropriate strategy for every website, and other Internet marketing strategies can be more effective like paid advertising through pay per click (PPC) campaigns, depending on the site operator's goals. Search engine marketing (SEM), is practice of designing, running, and optimizing search engine ad campaigns.^[52] Its difference from SEO is most simply depicted as the difference between paid and unpaid priority ranking in search results. Its purpose regards prominence more so than relevance; website developers should regard SEM with the utmost importance with consideration to PageRank visibility as most navigate to the primary listings of their search.^[53] A successful Internet marketing campaign may also depend upon building high quality web pages to engage and persuade, setting up analytics programs to enable site owners to measure results, and improving a site's conversion rate.^[54] In November 2015, Google released a full 160 page version of its Search Quality Rating Guidelines to the public,^[55] which now shows a shift in their focus towards "usefulness" and mobile search.

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.^[56] 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.^[57] It is considered wise business practice for website operators to liberate themselves from dependence on search engine traffic.^[58] In addition to accessibility in terms of web crawlers (addressed above), user web accessibility has become increasingly important for SEO.