Behavioral targeting
Partner sites on the Advertising Network can display customized ads suited to the individual interests of each user. The individual interests of users are determined by their behavior when using Yandex services or their behavior on partner sites. This method for ad delivery helps prevent users from seeing ads that they have no interest in whatsoever. We also consider possible declines in interest toward certain themes by distinguishing user interests as permanent or temporary: when preferences change, so do ads.
Note
Yandex will never apply this ad delivery approach if the ad concerns personal matters (for example, singles ads, medical ads, etc.). Exceptions are: sunglasses, baby thermometers, blood pressure monitors, first aid kits, warming pads, thermometers, heart rate monitors, immune response modifiers, anti-inflammatory agents, antipyretics, painkillers, antitussives, as well as antiallergic, antimicrobial, and antiviral medicine (see Yandex Direct Help for more information).
Yandex began using behavioral targeting advertising in 2008. At that time, only one factor was considered when displaying ads - the user's recent search history. Now we employ 8 different types of targeting based on information about users of our partner sites, and we are making continual developments in this area.
Why behavioral targeting is useful
Behavioral targeting is most effective for sites containing a broad range of themes and whose target audience is difficult to clearly distinguish based on page context. Adding behavioral targeting to contextual targeting helps substantially increase the size of the target audience to which we can offer advertisers access.
Available statistics show that, for the majority of ad platforms, the Click-Through-Rate (CTR) of ads displayed based on user interests is higher than the CTR of theme-based ads.
Collecting data on users' individual interests
Users' interests are determined by special files that are installed on their computers cookies. All data processed by Yandex is protected by our Non-disclosure agreement and may not be disclosed to third parties. If for any reason a user does not want their personal interests to affect the ads displayed to them, they can opt out of targeted ad delivery.
Selecting which ads to display
In simplified terms, ad selection based on user interests can be described as follows:

Contact support
If you didn't find the information you were looking for, check the FAQs or contact us.
I don't like the ads that were selected for my site
To disable impressions for ads that link to certain domains, you can block unwanted ads.
If you feel that the text or images displayed in ads violate the Yandex ad placement rules or Russian law, or have a negative impact on your traffic and user activity, please contact us via the feedback form. In your message, indicate the link that the ad directs to (a link like http://yabs.yandex.ru/count/... or http://an.yandex.ru/count/...) and send a screenshot of the page.