SEM is most important for the businesses who sell goods and services online or who use their websites to generate sales leads. Other goals for SEM including: building a brand, enhancing reputation with investors, generating media coverage, and driving traffic to physical business locations. Organizations such as non-profits, universities, governments, and political parties also use SEM to promote their ideas.

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. See the article on search engine optimization for details.

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 as unfair or deceptive.

Be careful of websites who claim guaranteed search engine positioning. There are three common traps to be mindful of when shopping for search engine positioning services.

The FIRST misleading guarantee is the empty promise of, "We guarantee you top rankings or we will continue to work on it until we do." In most cases, this simply means that they will continue to sit on their hands and do nothing. Why? because they already have your money. They are not really interested in renewals, they are very happy to simply take your initial fee. There is no real risk to them.

The SECOND misleading offer is when a company promises you first page listings on Google and/or Yahoo, but fail to tell you that they are talking about “sponsored listings” and not “natural listings." They charge you a set monthly fee and end up spending only a tiny portion of this fee on traffic from sponsored listings.

The THIRD and most common misleading guarantee is the "money back guarantee." This includes a guarantee that a certain percentage of your target keywords will receive top rankings within the major search engines such as Google and Yahoo. However, read a little deeper in their service agreement and you will see that their list of major search engines includes seven or more small and outdated search engines which are very easy to generate top rankings in. This is the catch. While they will verbally focus on Google and Yahoo over the phone, the small print reveals the truth. They end up easily meeting their guarantee and you are still no where to be found on the search engines that really matter.

Only the search engines themselves can truly guarantee top placement, and for ethical reasons, they can only do so legally through sponsored listings. Searching for a reliable Search Engine Marketer should rely on sample success stories and client referrals.

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.