Many forms of search engine optimization only amount to ensuring compliance to search engines’ guidelines for inclusion and removing any technical barriers that might keep the website from reaching a proper ranking. However, other methods of search engine optimization such as keyword spamming are often viewed as “gaming the system” and considered unethical.
Displaying advertisements or sponsored results in an area visually separated from the algorithmically determined results is generally considered ethical. However, some search engines allow the ranking of a website to be influenced with a payment and provide little or no indication to the end-user that this has happened. Since the search engines give the impression or claim that the rankings reflect the relevance or popularity of the websites, this is often seen unfair or deceptive.
Search engine advertising products that don’t guarantee a specific ranking or an amount of visibility are seen as unethical by some search engine marketers. The product might provide an unspecified “boost” or the final ranking or visibility might be a result of an auction.
Search engines use computer programs called spiders or web crawlers to automatically discover websites and catalog their content. As this process can take some time and requires a website to be linked to from another website (to allow the crawler to find it), most search engines except for Google provide another channel to be included in search rankings via paying. This is different from pay per click advertising because the inclusion is guaranteed but not placement.
Paid inclusion has not caused much concern. However, it has been suggested that search engines should improve the speed they pick up new websites and that paid inclusion services thus create a conflict of interest that discourages improving service levels across the board.