We would probably assume that all sites require search engine optimization. One of the reasons is because web sites were built online for audience to see, interact and hopefully make money out of them. While we don’t expect all web sites are made to make money, there is little reason we don’t do optimization because web sites exist to be noticed and not to be ignored.
If we examine all types of web sites, we think not all of web sites require SEO. Here are the possible scenarios:
Company intranet or niche group web pages
They are called intranet because they are intended for internal use only and must not be accessible from elsewhere. Intranets are typically password-protected so access is limited to authorized people. Training tool for employees or web-based classroom assignment for students could also fall within this category because they attract interest only to specific groups and not strangers who are not aware of certain methodologies and techniques included within the content of these web sites.
Optimally performing web sites
This is an ideal situation where our sites are performing very well (whether or not we did prior SEO) in terms of visitor traffic, sales and conversion rates. Doing SEO on these sites may be detrimental to their current performance because changes may bring adjustments on search engine index and the way pages are ranked.
Sites that are planned for massive revamp
Due to the characteristic of SEO that it takes relatively longer time to see the results than other marketing efforts (paid search, email marketing, etc), it would be counterproductive to do SEO in a site that will be torn down in a few weeks. Instead efforts on SEO will be devoted to the new site. A good case for this is that while the new site is being developed and SEO is being carefully planned, optimizing the old site could still pay off. This is advisable especially if no optimization has been done in the past and the new site won’t be available until at least three months later.
Even if the points above indicate that indeed it is not required for all sites, most probably SEO will still be required for sites described above. For example, the site that provides assignments to students online might be tied to other promotional offers intended to attract more students to enroll in that school, and showing these type of tests prove the quality of teaching methodologies in place. And the site that is revamped eventually needs SEO, once the new version is launched.