What is SEA and how does search advertising work?
SEA stands for search engine advertising. With Google Ads, a business pays to appear in results when someone searches chosen terms, usually paying only when there's a click.
Sylvain
What SEA means
SEA stands for search engine advertising. It's the paid side of search, in contrast to the organic work described in what is SEO. Most SEA spend goes through Google Ads, though alternatives such as Microsoft Advertising also exist.
Its biggest advantage is intent. Someone searching is expressing a need right at that moment. A well-built ad appears at exactly that instant, which is why paid search tends to convert better than awareness-only formats.
How the auction works
It isn't simply a list of whoever pays the most. Every time someone searches, the system runs an instant auction, combining what you're willing to pay with the estimated quality of your ad and landing page. A relevant ad with a coherent page can outrank a competitor bidding higher.
- Bid: the maximum you accept to pay per click, or your target cost per conversion.
- Quality: how relevant the ad is to the search, the landing page experience, and expected click-through rate.
- Extensions and formats: additional information such as location, calls, prices or site sections.
Cost per click and budget
In the cost-per-click model, you pay when someone clicks, not when the ad is shown. Cost per click varies enormously by industry and competition. Rather than asking how much a click costs, it's more useful to ask how much a customer is worth. If a new customer is worth several thousand euros over time, a higher cost per enquiry can still be profitable.
Keywords and targeting
Keywords define when your ad can appear. Generic terms bring volume and waste, specific terms bring less volume and better quality. Broad, phrase and exact match control that openness, and negative keywords are just as important for excluding irrelevant searches, such as people looking for jobs or training rather than your service.
Beyond keywords, you can target by location, time of day, language and device type. For local businesses, tightening the geographic radius is usually the first serious saving.
Landing pages
The ad buys the visit, the page decides the outcome. Sending all traffic to the homepage is a common waste. Each ad group should lead to a page that continues the same promise, with a clear call to action and no unnecessary steps. That's why we build campaigns alongside dedicated conversion pages.
Tracking conversions
Without tracking, advertising is just opinion. At minimum, record submitted forms, calls started, quote requests and, for e-commerce, purchases with value. With proper cookie consent and a clean setup, you can tell which campaigns generate business and which only generate clicks.
| Metric | What it shows | Watch out for |
|---|---|---|
| Impressions | Potential reach | Meaningless on their own |
| Click-through rate | Ad relevance | High with the wrong audience is misleading |
| Cost per click | Competitive pricing | Low doesn't mean profitable |
| Cost per conversion | Real efficiency | Depends on accurate tracking |
| Conversion value | Return on investment | Needs real business figures |
SEO and SEA together
Campaigns give fast answers about which messages and terms generate real demand. That information improves service pages and the content plan. At the same time, a fast, well-structured site improves ad quality and lowers cost per click. The choice between the two is covered in detail in Google Ads or SEO.
Frequently asked questions about Google Ads
What's a reasonable minimum budget?
It depends on your industry's cost per click. As a rule of thumb, aim for enough volume to collect dozens of clicks per week per campaign, otherwise there isn't enough data to optimise.
Is it worth bidding on your own brand name?
Often yes, especially when competitors bid on that term. The cost tends to be low, and it protects the enquiry from people already searching for your brand.
Do automated campaigns replace management?
No. Automation helps with bidding, but it still depends on the right goals, negative keywords, creatives and well-built landing pages.
About the author
Sylvain
Founder, WebCastelo
Sylvain is the founder of WebCastelo and works every day on websites, online stores, booking systems, custom software, SEO and digital advertising for companies in Portugal and the rest of Europe. He writes about what he sees in real projects: what works, what costs money without a return and what is worth doing first.
