What's the difference between SEM and SEO?

Added 11.04.11

With all the complicated acronyms floating around the IT world, it can be incredibly easy to become frustrated trying to decipher them and remember what they all refer to. To try to ease the burden a little, we'll now at least attempt to clear up the difference between SEM and SEO which are two processes that should never be confused.

Although the shorthand terms are unfortunately similar, and they both have something to do with online marketing, SEM and SEO are really, fundamentally different processes. SEM, or search engine marketing is a phrase that represents the use of the brief text advertisements that are programmed to appear at the top or in the right hand margin of a search engine results page. These generally appear under a heading that reads 'sponsored links' and are advertisements that have been purchased from Google or any other search engine, by the represented company. SEM is also sometimes known as PPC – yet another acronym that translates to 'pay per click'. This means that the owner of the ad only pays for their advertisement when a searcher actually clicks on the link, rather than each time is is displayed. The one similarity between SEM and SEO, as we shall see, is that they are both text that is displayed as a result of certain relevant key search terms being typed into the search engine search box. SEM or PPC ads are often priced according to the popularity of the key word phrases that their headings will represent.

In contrast, SEO or search engine optimisation is a term that refers to the process of actually designing web pages in a way that encourages the sites to appear naturally among the top organically generated listings on a search engine results page. Websites that are built with SEO principles in mind pay attention to the way in which search engine results are generated algorithmically. SEO specialists arrange a specifically determined percentage of keywords and keyword phrases throughout website content in order to appeal to the search engine's mathematical algorithms and ensure that the web page will be considered a top search result according to the frequency in occurrence of the relevant keywords used. SEO is a more long-term approach to online promotion than SEM, but it is also more economically viable and more successful in the long run because there are no ongoing payments required to the search engines and searchers often prefer to follow the naturally generated search result links over the links generated through paid advertising.

Fans of SEM generally cite that its main advantage over SEO is its effectiveness as an instant solution with instant results. Unlike SEO tactics, PPC ads can prepared to go live in barely over an hour and no changes are required to the actual structure or content of the website being advertised. However, what first seems like an easy solution can actually rack up debt because you are liable to pay per click for any traffic, which may or may not equal genuine and profitable visits to your website. If you are seeking a value for money approach to online promotion, SEO is definitely the way to go.