Below is a list of frequently asked questions to help you understand behavioural advertising.

What is online behavioural advertising?

Online behavioural advertising is a way of using information about your web browsing activity to group you with other users into interest groups and serve you advertisements based upon these interests.

Behavioural advertising differs from other forms of advertising on the internet such as contextual advertising, which is provided in response to your current, session-based activities (including search queries or websites visited).

How does it work?

There are different ways to provide behavioural advertising. At a basic level, information about your web browsing activity – together with information about thousands of other users’ browsing – is collected and segmented into general groups, such as cars, finance and travel. An interest profile (for example – “cars”) is inferred from data about the sites you have visited and a file known as a cookie is placed on your computer to identify you as someone interested in the category “cars”. Advertisers and websites will tailor adverts for groups of users with the same interest and the cookie enables such relevant display advertising to be delivered to you.

What data are used?

Behavioural advertising can vary in terms of what information is used and how. Traditional advertising networks, for example, collect and use information when you visit one or a number of websites participating in that particular network.

What are the benefits?

You receive online display advertising that is relevant to you and your interests. For example, if you’re interested in gardening and visit gardening websites, you may – in the same or a later online session – receive advertising for special offers on lawnmowers.

More targeted advertising is beneficial as you’ll receive more relevant adverts as well as access to free quality content, services and applications. It is beneficial to advertisers as they are able to reach the audience that is most likely to be interested in this information, leaving out those who are not likely to be interested. It is also beneficial for web publishers as advertising allows them to continue to provide free content and make that advertising more relevant to their users. This advertising revenue helps to fund future innovations and services on the internet.

Isn’t this a threat to my privacy?

All providers of this sort of service have to comply with applicable laws. In most cases, the information used for targeting adverts is not personal, in that you – the user – cannot be identified. Where personally identifiable information (like registration data) is used, you will have been told about it in the website’s privacy policy and given your consent when you registered for the service in question. You always have a choice as to whether to benefit from more relevant advertising or not.

What is ‘personally identifiable information’ and will it be used for online behavioural advertising?

Personally identifiable information is data that, by themselves or in conjunction with other data held by a particular company, uniquely identify you as a person. Obvious examples include your name, address or email address. Most providers do not use personally identifiable information for behavioural advertising. However, if a provider does use this information about you, you will have been told about it in the website’s privacy policy when you registered for a particular service.

What can I do if I don’t want this type of advertising?

You can opt out here.

It is important to remember that this does not mean that you will no longer receive advertising when you are using the internet. It just means that the advertising you see displayed on websites will not be customised to you and your interests and may be less relevant to you.

For further information please visit our opt out help page.

Does online behavioural advertising mean I will see more advertising?

No. It simply means that the advertising you see on some websites will be more relevant to you and your interests.

Will my online experience be disrupted by online behavioural advertising?

No. You will not see or experience any difference when online. Behavioural advertising simply aims to make display advertising more relevant to you.

Will any software be downloaded on my computer?


What is a ‘cookie’ and how is it used?

cookie is a small file of letters and numbers downloaded on to your computer when you access certain websites. Cookies allow a website to recognise a user’s preferences as previously chosen by the user when they return to a site. A cookie itself does not contain or collect information. However, when it is read by a server in conjunction with a web browser it can help a website deliver a more user-friendly service – for example, remembering previous purchases or account details.

Cookies are filed in the memory of your browser and each one typically contains:

  • The name of the server the cookie was sent from
  • The lifetime of the cookie
  • A value – usually a randomly generated unique number

The website server which sends the cookie uses this number to recognise you when you return to a site or browse from page to page. Only the server that sent a cookie can read, and therefore use, that cookie. Cookies are central to the customisation of the internet and online behavioural advertising usually works using cookies.

Can I disable a cookie?

Yes. Some browsers will let you block just third party cookies (this is a cookie placed on your browser by a third party – for example, an advertising network – other than that particular website owner) or will allow the use of settings to block only cookies that do not meet your privacy preferences.

You can choose to disable all cookies but this could significantly affect your web browsing experience if you use services that rely on cookies. Visit our top tips to find out more about managing your web browser privacy settings.

Will I have to opt-out if I use a different PC at work?

Yes. If you choose to decline behavioural advertising from a specific company, it only applies to that particular company’s data collection and use on the internet web browser on the computer or device you are using. It will therefore affect other people who use that web browser as well. You will need to follow the same process on every computer you use or different web browser (eg Internet Explorer, Google Chrome, Mozilla Firefox or Safari) that you use to fully decline behavioural advertising from that particular provider. For more information about opting out please visit our opt-out help page.

Does disallowing behavioural targeting prevent me from receiving spam, pop-ups or junk mail?

No. Declining behavioural advertising only means that you will not receive more display advertising customised in this way. It does not affect or disallow any particular type of advertising e.g. email or pop-ups.

Do I need to do anything?
Have a quick look at our five top tips.

Who can I contact for further information?

Send us your privacy@edaa.eu