Search engine marketing (SEM) is the practice of getting a business in front of people while they search on engines such as Google and Bing. In current UK usage it nearly always means paid search advertising, although some people still use it as an umbrella covering both paid ads and SEO.
How search engine marketing works
In paid search, you choose the searches you want to appear for, write ads and set a budget. When someone searches, the platform runs an ad auction in a fraction of a second. Your position and price depend on your bid and on how relevant and useful the platform expects your ad and landing page to be, reflected in measures such as Quality Score. You normally pay only when someone clicks, which is why paid search is also called PPC.
The two main platforms in the UK are Google Ads and Microsoft Advertising, which serves ads on Bing, Yahoo and partner sites. Beyond plain text ads on search results, SEM campaigns can include shopping ads with product images and prices, call ads for mobile users and, where Google offers the format, ads shown alongside its AI-generated answers.
When people use SEM to include SEO, the organic side works differently: you cannot pay for those positions, so visibility comes from content, technical health and authority built over time.
Why it matters
Search is where people go when they already have a need. Someone typing “emergency boiler repair Croydon” or “VAT accountant for contractors” is asking for a supplier, and SEM puts you in front of them at that moment. Paid search is also fast: a well-built campaign can bring enquiries within days, while organic rankings for competitive terms take months.
The trade-off is cost. Clicks in sectors such as legal services, insurance or home improvement can be expensive, and spend stops producing results the day you stop paying. Most UK businesses get the best value by running paid search for commercial terms where they need leads now, while building organic visibility that reduces dependence on ads over time.
Paid search also gives precise control that organic results cannot. You can show ads only within a set radius of your premises, only during opening hours, or only on mobile for call-led services, and switch them off when the diary is full. For a London trade business that covers a few boroughs, that control alone can make the difference between profitable and wasted spend.
Common mistakes
- Broad targeting with no negative keywords. Budget leaks to irrelevant searches, such as “jobs”, “free” or “DIY” variants of your service.
- Sending every ad to the home page. A landing page that matches the search converts far better than a generic page.
- No conversion tracking. Without calls, forms and sales recorded, automated bidding optimises for clicks rather than customers.
- Treating SEM and SEO as rivals. Search terms data from ads shows which phrases convert, which is valuable when planning organic content.
- Accepting every automated recommendation. Platform suggestions often raise spend before they raise results.
How to act on it
Start by listing the searches that signal real buying intent for your service, and the areas you cover. Set up conversion tracking for calls, forms and purchases before spending anything. Begin with a focused search campaign on those terms, with tightly matched ads, dedicated landing pages and a negative keyword list, then review the search terms report every week for the first month.
If you want campaigns built and managed around enquiries rather than clicks, my Google search ads management service covers the structure, tracking, copy and ongoing optimisation.