In many respects, advertisements drive the web. The biggest web companies today — yes, Google and Facebook — get most of their revenue from advertisements, but also many small web sites can exist because of advertising. So, as we work at Searsia to provide developers with open source tools to build beautiful search engines, we also want to provide them with easy ways to include advertisements alongside the search results. For, why would people make beautiful search engines if it only costs them?

Advertisers and publishers

If you plan to put advertisements along-side your search results, then the terminology used in online advertising can be confusing. The Wikipedia page on on-line advertising distinguishes advertisers that buy advertisement space and publishers that sell advertisement space. Obviously, if you are building a search engine that displays ads, then you are a publisher — even though a search engine merely directs users to the real publishers. As a publisher/seller you will interact with advertisers/buyers through an advertising network, a company that connects advertisers to publishers.

Advertising platforms

Online advertising is highly automated on platforms that facilitate the buying and selling of advertisement space. Such platforms, often called ad exchanges, serve multiple ad networks. Platforms are increasingly specializing towards either buying ad space or selling ad space, in which case they are called demand-side platforms or supply-side platforms. Platforms determine the prices of the advertisement space through bidding: Advertisers bid on advertisement space by deciding what they are willing to pay for each impression of their ad or for each click on their ad.

Real-time bidding

This bidding process within an ad exchange can be very dynamic. In real-time bidding, advertising space is bought and sold on a per-impression basis. Real-time bidding sounds fascinating, but it is really a search: The platform searches the best advertisement based on various pieces of data, such as the user’s demographic information, browsing history, and location. The more accurate the behavioral targeting of users, the more the advertisement network earns. That’s why networks track users online. They profile users by “following” them around to gather as much data on users as possible. This way, when a user reads an article on a publisher’s web site, say a real publisher like a newspaper, the advertisement network can guess what advertisement the user is willing to click, and ultimately what product a user is willing to buy.

Real-time bidding without tracking

Real-time bidding for search engines is much easier than real-time bidding for a newspaper site: Users of search engines tell the search engine explicitly what they are willing to click on. What would be a good ad for the query “car”? Right, an ad for the Tesla Model 3, for instance! There is absolutely no real need to track users for search ads. DuckDuckGo describes this aptly on the DuckDuckGo company pages:

It is a myth that search engines need to track you to make money on Web search. When you type in a search, we can show an ad just based on that search term. For example, if you type in, “car” we show a car ad. That doesn’t involve tracking because it is based on the keyword and not the person.

OpenRTB: Open Real-Time Bidding

Interestingly, there is an open standard for real time bidding called OpenRTB. OpenRTB was launched in late 2010 by six companies in online advertising, representing both demand-side and supply-side platforms. The standard is actively maintained by the Interactive Advertising Bureau (IAB), and its latest version, OpenRTB version 2.5, was released in December 2016.

Many advertisement platforms support OpenRTB, usually version 2.3, which is currently the most widely adopted release. Examples are SSPHWY, DataXu, OpenX, BrightRoll (by Yahoo), DoubleClick (by Google), and RythmOne that claimed last week that it provides the first IAB certified implementation of OpenRTB.

OpenRTB Native ads

One of the biggest changes in OpenRTB version 2.3 compared to previous versions is the support for native advertising. Native advertising provides ads that match the form and function of the site on which they appear. One of the main examples of native ads are search ads: ads that appear within search result pages.

The difference between native ads and traditional display ads comes down to metadata. Display ads, such as the traditional banner ad, need only an image of predefined size. Native ads however, provide several separate pieces of information like a title, a summary, a thumbnail image, and the brand’s logo. This way, its appearance can be tailored to a publisher’s content feed or a search engine’s result page. Of course, advertisements should always be clearly marked such that they are recognized as paid content by the users.

OpenRTB comes with a separate specification for native ads, OpenRTB Native 1.2, which contains a detailed explanation of the sub-protocol of the OpenRTB real-time bidding interface for native ads.


To conclude, on-line advertising using real-time bidding sounds fancy, but it really is just the advertisement platform searching its ads database for the best ad for a single impression. Furthermore, real-time bidding for a search site is more easy than real-time bidding for many other sites, because the advertisement network can show an ad based on the user’s search query, without the need to track the user. Finally, there is an open standard for real-time bidding, fittingly called OpenRTB, that is used by many advertising networks and that includes a detailed subprotocol for native search ads.

At Searsia, we are currently investigating how to deliver native search ads using the OpenRTB standard. Stay tuned if you want to monetize your Searsia federated search engine.