Search engine marketing (SEM)
What is search engine marketing?
Search engine marketing (SEM) is promoting a website through search engines. Today it usually means paid search advertising, such as Google Ads and Microsoft Advertising, where you bid on keywords and pay per click. Some people use SEM as an umbrella term for both paid search and SEO.
Paid search works on an auction. You choose keywords, write ads and set bids; the search engine shows ads based on bid and quality, and you pay when someone clicks. The cost per click for a keyword is a useful SEO metric too, because it shows how commercially valuable that search is.
Paid ads appear in labelled “Sponsored” slots on the SERP, usually above and below the organic results, and sometimes in shopping and local results. Clicking an ad and clicking an organic result look similar to a searcher, which is why many businesses plan both together and compare the cost of each click against the traffic value of their organic rankings.
Why search engine marketing matters for SEO
SEO and paid search target the same results page and complement each other. Ads bring traffic immediately and let you test keywords and copy; SEO builds traffic that doesn’t cost per click and takes longer.
Ad data, such as which keywords convert, can tell you which topics to prioritise for SEO.
How to combine SEO and paid search
- Use ads to test which keywords and messages convert before investing in SEO content.
- Use high-CPC keywords as a signal of where organic rankings would be most valuable.
- Reduce ad spend on queries where you rank well organically, if tests show the clicks move to organic.
- Share title and description wording that performs well between ads and organic pages.
Search engine marketing FAQ
What is the difference between SEO and SEM?
SEO earns unpaid rankings; SEM, in its common meaning, is paid search advertising. In the broader definition, SEO is part of SEM.
Is PPC the same as SEM?
PPC (pay per click) is the payment model behind most search ads, so the terms are often used interchangeably. PPC also covers ads outside search, such as social ads.
Related SEO terms
SEO (search engine optimization)
SEO (search engine optimization) is the work of making your website easier to find, understand and choose in unpaid search results.
Paid search results are ads shown on search results pages, labelled Sponsored on Google, where advertisers pay when someone clicks.
Cost per click (CPC) is what advertisers pay for one click on a search ad. In SEO, a keyword’s CPC hints at how commercially valuable it is.
Organic search is the unpaid part of search results, where pages appear because the search engine judged them relevant, not because someone paid.
Traffic value estimates what a site’s organic traffic would cost if you bought the same clicks with search ads, using each keyword’s CPC.