Paid inclusion is a search engine marketing method in itself, but also a tool of search engine optimization, since experts and firms can test out different approaches to improving ranking and see the results often within a couple of days, instead of waiting weeks or months. Knowledge gained this way can be used to optimize other web pages, without paying the search engine company.
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. 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. It is considered a wise business practice for website operators to liberate themselves from dependence on search engine traffic. In addition to accessibility in terms of web crawlers (addressed above), user web accessibility has become increasingly important for SEO.
Since social media marketing first came to be, strategists and markets have been getting smarter and more careful with the way they go about collecting information and distributing advertisements. With the presence of data collecting companies, there is no longer a need to target specific audiences. This can be seen as a large ethical gray area. For many users, this is a breach of privacy, but there are no laws that prevent these companies from using the information provided on their websites. Companies like Equifax, Inc., TransUnion Corp, and LexisNexis Group thrive on collecting and sharing personal information of social media users. In 2012, Facebook purchased information from 70 million households from a third party company called Datalogix. Facebook later revealed that they purchased the information in order to create a more efficient advertising service.
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. 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.