Paid advertising platforms: the main ones, the three ways they are bought, and what each route costs to enter

There are only about thirty paid advertising platforms a normal business needs to know, and they fall into six groups by the kind of demand they sit next to: search, social, retail and marketplace, video and connected television, audio, and the open web bought programmatically. The list is the easy part. The decision that actually sets your minimum spend, your targeting, your reporting and how quickly you can stop is the buying route, and there are only three of those. You either open an account yourself and bid in an auction, you buy inventory across many publishers through a demand side platform, or you sign an insertion order with a seller. Pick the route before you pick the platform, because the route is what you are really committing to.

This page lists the platforms, explains the three buying routes, and gives the order to add them in. For the fee structures on the agency side of the same purchase, see how a media buying agency handles your money.

The platforms, grouped by the demand they sit next to

Group them this way rather than by company, because two platforms in the same group compete for the same budget and do the same job for you.

Group	The main platforms	What you are buying
Search	Google Ads, Microsoft Advertising	A query somebody typed, so the demand already exists
Social	Meta (Facebook and Instagram), TikTok, LinkedIn, Pinterest, Snapchat, Reddit, X	An audience described by who they are and what they do
Retail and marketplace	Amazon Ads, Walmart Connect, Instacart, Target Roundel, eBay, Etsy	Placement at the point of purchase, next to the product itself
Video and connected television	YouTube inside Google Ads, Amazon, Roku, Disney, Netflix, Paramount, Samsung and LG	Attention on a screen, sold by the thousand impressions
Audio	Spotify, SiriusXM and Pandora, Acast and the podcast networks	A listener, usually bought by show or by audience segment
Open web, bought programmatically	Google Display Network, Display and Video 360, The Trade Desk, Amazon DSP, Microsoft Advertising with Xandr, Criteo, Taboola, Outbrain	Inventory on thousands of publisher sites and apps at once

Two things worth knowing about that table. First, several companies appear in more than one row, because one login now sells several groups: a Google Ads account reaches search, YouTube, shopping and display, and Microsoft Advertising reaches search, retail, display and connected television. Second, the list of sellers in the bottom row is the one that changes most often, because it is the layer with the most companies in it.

The three buying routes, and why the route is the decision

	Self serve auction	Programmatic through a DSP	Direct or managed
How you get in	Open an account, add a card, launch today	A seat on a demand side platform, usually through an agency or a reseller	A conversation, a proposal and a signed insertion order
Typical entry cost	Nothing to open, and you set the daily budget	A monthly or quarterly commitment, plus a platform fee	A campaign minimum set by the seller
What sets the price	An auction against other advertisers for each impression	An auction, plus the fees stacked on top of the media	Negotiation, and a rate card you can argue with
Targeting control	High inside that platform's own data	Widest reach, and you can bring your own audience data	Whatever the seller can offer, often a show, a channel or a section
What you can see afterwards	Full reporting inside the platform, and nothing outside it	Log level detail if your contract gives you access to it	A delivery report, which is the weakest reporting of the three
How fast you can stop	Immediately	At the end of the commitment	At the end of the flight, and cancellation terms are written in the order

Read that table as a single trade. Self serve gives you speed and the right to walk away, in exchange for only reaching what that one company owns. Programmatic gives you reach and your own data, in exchange for fees you have to go looking for. Direct gives you a named placement and a human being who answers the phone, in exchange for the least flexible money you will spend all year.

Four questions that tell you which route you are actually in

• Could you have started with a card? If yes, it is self serve, whoever sent you the proposal.
• Is there a minimum, a flight date or a signature? Any of the three means you are in a direct or managed buy, and the terms matter more than the creative.
• Can you see the names of the sites and apps your money landed on? A placement report by domain means programmatic. A total impression count with no breakdown means somebody is buying on your behalf and reporting a summary.
• Who holds the audience and the conversion data when this ends? On self serve the platform keeps its own and you keep your analytics. On programmatic the answer should be in the contract. On a managed buy it is often the agency, and that is the single clause worth reading twice.

The order to add platforms

Almost every business that spends well follows this sequence, and almost every business that wastes money skips a step.

• Start where the demand already exists. If people search for what you sell, a small search account on your brand terms and your five best commercial queries is the first money. It is the cheapest honest test of whether your offer converts at all.
• Then retargeting. Bringing back people who already visited is the lowest cost conversion on any platform, and it works on Meta, on search display and through any DSP.
• Then one platform that creates demand. One, not three. Choose it by where your buyer already spends attention, give it its own metric, and hold it for long enough to read.
• Then retail media, if you sell a product somebody buys on a marketplace. This is the closest paid placement to a transaction that exists, and the feed quality decides the result more than the bid does.
• Then video, connected television, audio or programmatic. These are reach purchases, and they belong after you have a measurement setup that can see an effect that does not arrive as a click. Our guide to connected television advertising and where the inventory comes from covers the one most businesses reach for first.

The five costs to separate before you sign anything

On a self serve account the whole bill is media. On every other route the bill has layers, and the only way to compare two proposals is to make somebody split them out.

• Media. What actually reaches the auction or the publisher.
• Platform fee. The DSP or the ad server, usually a percentage of media.
• Data fee. Third party audience segments, charged per thousand impressions on top of the media.
• Management fee. The agency or the in house team. A percentage of spend rewards spending; a flat fee rewards the work.
• Verification and measurement. Fraud, viewability and brand safety tools, which the buyer usually pays for separately.

Ask for one number: of every dollar you hand over, how many cents reach a publisher. A seller who can answer that quickly is a seller worth working with.

Measuring platforms against each other without fooling yourself

Every platform reports the conversions it believes it caused, using its own window and its own rules, so adding up the platform dashboards gives you more conversions than your business had. Three habits fix it.

• Pick one source of truth. Your own analytics or your own order system, with one agreed conversion definition and one attribution window applied to every platform.
• Judge demand creating platforms on a holdout, not a dashboard. Turn the platform off in a set of regions for four to six weeks, change nothing else, and compare total enquiries and branded search between the held out group and the rest.
• Keep an open text question on your enquiry form. Asking how somebody heard about you catches the advertisement they saw three weeks before they searched, and it costs nothing to run.

Paid advertising platforms: what buyers ask

Which paid advertising platform should a small business start with?

The one that sits next to demand you can already see. Search your own category and look at whether there are ads above the results: that tells you other people are paying for those clicks and finding it worthwhile. If nobody searches for what you sell, start on the social platform where your buyers already spend time, and start with retargeting your own visitors.

What does it cost to get onto a platform?

Opening an account on any self serve platform is free, and you set the daily budget yourself. The real floor is the budget that buys enough clicks to learn something, which depends on what a click costs in your category. Programmatic and direct buys set their own minimums, and those are negotiated rather than published.

Do I need a demand side platform?

Only when you need reach across the open web, your own first party audience data applied to inventory one platform cannot sell you, or control over where your advertisements appear at a level the self serve networks do not offer. Below that, the self serve platforms cover the same ground with less cost and less contract.

What is the difference between an ad network, an ad platform and a DSP?

An ad platform is one company selling its own inventory, such as Google Ads or Meta. An ad network aggregates inventory from many publishers and resells it as packages. A demand side platform is software you use to bid on inventory across many exchanges, with your own data and your own rules. The first is the simplest, the last gives you the most control, and the middle one sits between them.

Can the same creative run on every platform?

The message can. The asset usually cannot, because the formats are different and the first two seconds work differently on a scroll than on a television. Build one message and produce it in the three shapes you need: a vertical video, a square image set and a line of text that matches a query.

When can a platform be judged?

Long enough to collect a few hundred clicks on search, and long enough to collect a reasonable number of conversions everywhere else. Reading a platform after a week of small spend tells you about the week, not about the platform.

The surface where there is nothing to buy

Every platform above has an auction or a rate card, which means every competitor can reach the same place you can by paying. There is now one surface in the buying journey that has neither. When somebody asks ChatGPT, Gemini or Perplexity for the best option in your category, an answer with a shortlist comes back, and no advertisement in it was sold. The inputs are what the web already says about the companies named. Worth adding to your next media review as a single question: when a buyer asks an assistant for a recommendation in our category, which companies does it name, and are we one of them? AI Knows Us was built to ask that across the main assistants and record the names and the sources behind them.