What is a search feed?

In the foundations track, the feed was a black box: visitors go in, revenue comes out. This track opens the box. A search feed is a contractual and technical connection that lets a website outside Google, Bing or Yahoo show that search engine's paid ads against a search term, and receive a share of what advertisers pay for the clicks.

Think of a soft drinks company and a corner shop fridge. The company owns the drinks, sets the price and keeps the customers' loyalty. The shop provides the location. The fridge comes with conditions: where it stands, what else may go in it, and a right to take it back. A search feed is the fridge. The ads inside it never belong to the shop.

What actually travels through a feed

Each time a results page loads, the publisher's page sends an ad request to the search engine. It carries the search term, the publisher's identity, the language and country, and identifiers that describe the page and the traffic. The search engine runs its normal ad auction among advertisers who have opted in to partner sites, and returns a set of ads: each sponsored listing with a headline, description and click link.

1. A term reaches the results pageThe visitor typed it into a search box or clicked a related search term.
2. The page requests adsWith Google this happens in the visitor's browser through Google's own script. Some Bing and Yahoo integrations are instead made server to server.
3. The auction runsOnly advertisers whose campaigns include the search partner network can compete.
4. Ads renderThe publisher controls the look within approved limits, usually through a Style ID. It cannot edit the ads themselves.
5. A click is chargedThe advertiser pays the search engine. The search engine checks the click for validity and later credits the partner.

1. Advertisers bid at the search engines: An Advertiser sets up keyword campaigns in Google Ads or Microsoft Advertising. Almost all the money in search arbitrage starts in these few advertising systems. Yahoo’s search ads have for years been supplied largely through Microsoft.
2. Engines lend their ads out: Search engines also show those ads on other companies’ sites. This is search syndication, and the sites together form a search partner network. Think of a wholesaler stocking many small shops.
3. The feed provider holds the contract: A direct feed is a contract with the engine itself. Few companies have one. A feed provider (or syndication partner) does, and is answerable to the engine for everything shown under its account.
4. Sub-publishers plug in: The provider gives approved publishers a hosted feed in return for a share of revenue. Each publisher, site or campaign is tagged with a channel ID so the provider and the engine can see whose traffic is whose.
5. The ad reaches a visitor: The sub-publisher brings visitors, usually with paid traffic, and the engine’s ads appear on its results pages. The visitor rarely knows four companies stand between them and the advertiser.
6. Money flows back up the chain: A click charges the advertiser, say, $1.00. In our example the engine passes $0.70 to the provider, and the provider passes $0.56 to the sub-publisher. Each hop is a toll booth.
7. Responsibility flows down it: The engine audits clicks and pages across the chain. One sub-publisher with bad traffic can put the provider’s whole contract at risk, so providers police feed approval, traffic sources and volumes closely.

The three families of feed

Direct or hosted

A direct feed is a contract between the publisher and the search engine. These are scarce, come with an account manager and demand scale and a clean record. Everyone else uses a hosted feed: a feed provider with a direct contract lets the publisher operate under it. The provider often hosts the results page, or even the whole article page, on domains it controls, and gives the publisher a link and a reporting dashboard.

How a feed is measured

Feed reporting has its own vocabulary. A practitioner reads these numbers every morning:

• Coverage: the share of ad requests that came back with at least one ad. A term with no bidders returns nothing and earns nothing.
• Ad depth: how many ads were returned per request. More competing advertisers generally means higher prices.
• Ad CTR: clicks on ads divided by results-page views.
• RPC: revenue per ad click, the partner's share.
• RPS: revenue per search or session. Because it blends coverage, click rate and price, it is the best single measure of a feed's worth.

A worked example, with made-up numbers. Out of 1,000 results-page views, 900 return ads (coverage 90%). Those views produce 270 ad clicks, an ad CTR of 27% of all views. At an RPC of 80 cents the revenue is 216 dollars. RPS is 216 ÷ 1,000 = 21.6 cents. If coverage falls to 70% and nothing else changes, clicks fall to 210 and RPS to 16.8 cents. The term did not get cheaper; it simply had fewer advertisers.

Slicing the numbers: channels

One feed account may serve thousands of campaigns. To see which earns what, each request is tagged with a Channel ID. Revenue is then reported per channel, and the publisher's tracker maps channels back to campaigns, keywords or traffic sources. Channels are a limited resource on many feeds, which is why access to more of them, and to keyword-level reporting, is a real selling point between providers.