DefinitieMarketing through search engines, in practice mostly paid ads (Google Ads) that appear above or beside the organic results. Often contrasted with SEO, which earns unpaid visibility.
Search engine marketing (SEM) is marketing through search engines, which in practice mostly means paid ads (Google Ads) that appear above or beside the organic results. Search “wandelschoenen heren” and the row of Shopping tiles and text ads before the first normal result is SEM at work. It is usually contrasted with SEO, which earns unpaid visibility on the same page over a longer period.
The confusion starts with the word itself. Fifteen years ago SEM covered everything you did in search engines, organic and paid together. Today almost everyone who says SEM means paid search: Google Ads search campaigns, Shopping and Performance Max, and Microsoft Ads for Bing. When a shop owner tells me “we already do SEM” I ask what they mean, because often it turns out a Google Ads account is running and nobody touches the organic side at all.
Why SEM matters for a webshop
For commercial queries, the paid results have quietly taken over the top of the page. On a product search like “espressomachine kopen” the first mobile screen is often entirely Shopping and text ads, with organic position one below the fold. A webshop that relies on organic alone for these queries competes for whatever clicks are left after the ads; that share varies by study and query type, but it is smaller than most owners assume.
SEM also gives you something SEO cannot: speed and control. You can be visible for a new product line tomorrow, pause it when stock runs out, and see which search terms produced orders. For a Lightspeed shop launching a seasonal range, that is worth real money. The flip side is that the clicks stop the moment the budget stops, which is why I treat paid search as a partner to organic work, not a replacement.
How to measure SEM alongside SEO
Google Ads itself reports cost, clicks, conversions and the actual search terms that triggered your ads. For the full picture I pull that into GA4, where the default channel grouping separates Paid Search from Organic Search so you can compare revenue per channel on the same conversion definitions. Big gaps between the two usually point to a tracking problem, not a performance problem.
The most useful analysis sits between two exports. I take the search terms report from Google Ads and the queries report from Google Search Console and match them. Where a query appears in both, I can see the organic position next to the paid cost per click. In Looker Studio I build a blended view with both sources on one page, so the shop owner and the ads manager look at the same numbers; Ahrefs adds volume and difficulty estimates for queries that only show up on the paid side.
Common SEM mistakes
Paying for queries you already own. If a PrestaShop category page ranks first organically for “biologische hondenvoeding” and the shop also bids on it, a share of those paid clicks would have arrived for free. Defending the position can be justified when competitors advertise on it, but it should be a deliberate choice backed by a holdout test, not a default.
Keeping SEM and SEO in separate silos. The ads account knows within days which search terms convert; the SEO side often guesses for months. When the two never share data, the shop pays twice for the same learning; a monthly export of converting search terms is the cheapest keyword research a webshop can get.
Leaving brand terms unprotected. Competitors can bid on your shop name, and in some sectors they do. If nobody checks the SERP for your own brand, a rival ad may sit above your organic listing for months; a small brand campaign is usually cheap and keeps that spot yours.
Letting Performance Max hide what is happening. Performance Max and Shopping campaigns pull in queries you never chose, including your own brand and generic terms you rank well for. Without search term insights and brand exclusions, the campaign reports great results while quietly cannibalising organic traffic you already had.
How I handle SEM for clients
I am an SEO consultant, not a Google Ads specialist, so I do not build campaigns. I make sure the paid and organic sides of a webshop work from the same data. At the start of an e-commerce SEO project I ask for read access to the Google Ads account and run an overlap analysis: which queries are bought, which are ranked, and where both happen at once. That becomes a short list of decisions for the owner and the ads manager: queries to stop bidding on, queries to test before I invest in content, and brand terms that need a defensive campaign.
The ongoing deliverable is the blended dashboard and a quarterly review of it. Converting paid search terms feed my keyword planning: a term that converts in ads without an organic page goes on the content roadmap. When a category page reaches the top of the organic results, I flag it so the ads budget can shift to terms where the shop is still invisible. The goal is simple: pay for visibility only where you cannot earn it yet.
Veelgestelde vragen
Is SEM the same as SEO?
No. SEO earns unpaid rankings by improving your site and its authority; search engine marketing, as the term is used today, buys placements through Google Ads or Microsoft Ads. Both target the same results page and the same searchers, which is why they should be planned together.
Do Google Ads improve my organic rankings?
Not directly. Google states that ad spend does not influence organic results, and I have never seen evidence otherwise in client data. Ads help indirectly at most: more visitors, brand searches and reviews feed back into the organic side over time.
Should I stop bidding on keywords where I already rank first?
Test it before you decide. Pause the ads for a few weeks on a clear set of queries and compare total clicks and revenue (paid plus organic) with the period before. The answer differs per query: for brand terms with no competing ads you can often stop; for competitive product terms the Shopping tiles still take a large share of clicks.
Should a new webshop start with SEM or SEO?
Usually both, but with different jobs. Paid search brings the first orders and tells you quickly which products and queries convert. SEO takes months to build, so the earlier you start on the technical basics and category content, the sooner organic traffic takes over part of the work ads do now.