Eye tracking studies have shown that searchers scan a search results page from top to bottom and left to right, looking for a relevant result. Placement at or near the top of the rankings therefore increases the number of searchers who will visit a site. However, more search engine referrals does not guarantee more sales. SEO is not necessarily an appropriate strategy for every website, and other Internet marketing strategies can be much more effective, depending on the site operator’s goals. A successful Internet marketing campaign may drive organic search results to pages, but it also may involve the use of paid advertising on search engines and other pages, building high quality web pages to engage and persuade, addressing technical issues that may keep search engines from crawling and indexing those sites, setting up analytics programs to enable site owners to measure their successes, and improving a site’s conversion rate.

SEO may generate a 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. According to notable technologist Jakob Nielsen, website operators should liberate themselves from dependence on search engine traffic. A top ranked SEO blog Seomoz.org has reported, “Search marketers, in a twist of irony, receive a very small share of their traffic from search engines.” Instead, their main sources of traffic are links from other websites.