How Are SEO, SEM, and Backlinks Related?

SEO focuses on a website’s rankings in organic search results. Under the broad definition used in this article, SEM (search engine marketing) includes SEO and paid search advertising. Backlinks are links from other websites to your website. They are part of SEO, rather than a third strategy alongside SEO and SEM. High-quality backlinks can help improve a website’s credibility, authority, and search visibility, but organic rankings cannot be reduced to a competition over link counts.

First, clarify the scope: SEO is part of SEM

The iThome material defines SEM as a field of search marketing that encompasses SEO and paid search advertising. Under this definition, the two are not entirely mutually exclusive options; instead, SEO is part of the broader category of SEM. Although the material describes them as “two different strategies,” the scope it subsequently defines explicitly includes SEO.

• SEO: Aims to improve a website’s rankings in organic search results.
• Paid search advertising: The other component of SEM in the classification above.
• SEM: Used in this article to refer to search engine marketing that encompasses both.

When reviewing marketing proposals, therefore, first confirm what work the provider includes under SEM rather than judging by the label alone. The relationship described in this article follows this source’s definition; it is not presented as the only valid usage in every context.

Backlinks belong on the organic search side, within SEO

For example, when another website includes a link to a page on your website in an article, that is a backlink for your website. The key is that the link comes from another website and points to yours—not how many links you add within your own website.

The iThome material states that high-quality backlinks can strengthen a website’s credibility and authority, helping its visibility in search results. The qualification here is high-quality; this should not be recast as “all links have the same effect.” Under the relationship outlined above, backlinks fall within broadly defined SEM through SEO, but the material does not support the claim that they directly improve paid search advertising performance.

Understand the value of links while keeping algorithm explanations in their historical context

In a 2023 article, Screaming Frog noted that Google’s organic rankings involve hundreds of factors, at least one of which relates to backlinks. The article also used PageRank to explain the concept of value passing between pages through links, stating that this concept remained part of the algorithm at the time. This supports a connection between backlinks and organic rankings, but it is not enough to calculate how many positions a single link might gain.

In its retrospective on Panda, Semrush’s 2023 article distinguished between building a healthy backlink profile as a general SEO practice and Panda’s role, noting that Panda does not directly address backlinks and attributing such external factors to Penguin. This explanation of the algorithms has a historical context and should not be treated as a complete account of how current mechanisms divide their responsibilities.