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). Relevant ads can also be delivered based upon the website content you have just been viewing. This is known as ‘retargeting’.


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. This is information such as the website content that you visit, keyword searches that you make and ads that you may interact with. Each business will provide you with more information about information that they collect and use and this will be available by clicking on the new icon that is in the ads that you may see on websites. See our top five tips for further information.


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  quality content, services and applications at little or no cost. 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 websites (web publishers) as advertising allows them to continue to provide content at little or no cost 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?


The information collected and used for customising adverts is not personal, in that you – the user – cannot be identified. The EU Good Practice Principles were specifically designed to help safeguard your privacy. You always have a choice as to whether you wish to benefit from this type of advertising or not. More relevant advertising needs a little bit of information about your interests, otherwise it cannot work but we acknowledge that people may be uncomfortable with this. If so you can turn it all off here. You can also manage your privacy within the web browser that you are using. Visit our five top tips to see how to do this. Many web browsers also have a ‘private browsing’ mode as well.


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


You can opt out here. You can also manage your privacy within the web browser that you are using. Visit our top tips to see how to do this. Many web browsers also have a ‘private browsing’ mode as well.


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.


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. Advertising on the internet helps to pay for content and service, available at little or no cost.


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 the advertising you see on websites more relevant to you.


Will online behavioural advertising be directed at children?


The EU Good Practice Principles have a specific commitment that no business shall create or sell an interest or audience segment intended for the sole purpose of behaviourally targeting children they know to be under the age of 13 years.


What is this EU Good Practice and how is it relevant to me?


The EU Good Practice Principles are guidelines for businesses collecting and using online information for behavioural advertising. The aim is to provide you with transparent information and control over this type of advertising. At the heart of the Principles is a symbol or icon that appears in the advertisements on websites to provide you with this information and control. You can find out more about this icon in our five top tips.


How do I know businesses that have signed up are complying with these Principles?


Businesses that have signed up to the programme have to go through an independent verification process to show that they are complying fully. To demonstrate this, businesses are awarded a ‘trust seal’. You can see which businesses have achieved this here.



Does this EU Good Practice cover mobile and tablet devices?


You may come across the icon when using mobile or tablet devices. Industry plans to adapt its existing good practice for EU and EEA markets to provide people with greater transparency and control when using mobile devices. However, whilst existing EU good practice is technology-neutral, it is mainly applicable to the desktop online environment. Data collection and use differ slightly in the mobile environment and we are working on a seamless experience across all environments – desktop, mobile and tablet – for internet users. Further details on this will appear on this site.


Will any software be downloaded on my computer?

No. Behavioural advertising will not disrupt your internet speed or connection.

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. Please note: cookies are used for other purposes as well, and not just advertising.


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 five top tips to find out more about managing your web browser privacy settings.


What are ‘flash cookies’? Are they used to collect information for online behavioural advertising?


Flash cookies are a common form of file called a Locally Shared Object (LSO). LSOs are technologies that allow for the persistent storage and retrieval of information in relationship to an internet user’s web browsing experience but are typically not exposed via web browser controls (such as those for HTML cookies). Examples of their use include Adobe Flash and Microsoft Silverlight.


If technologies, such as LSOs, are used for behavioural advertising purposes this will not affect your right to turn off behavioural advertising and this can be done at here.


LSOs should never be used as a mechanism to avoid the operation of web browser controls or opt out tools commonly relied on by users to manage privacy preferences for behavioural advertising programmes. Any such implementation designed to bypass user controls and facilitate ‘respawning’ without a user’s explicit consent for this purpose is prohibited in the UK by the amended Privacy and Electronic Communications (EC Directive) Regulations 2011.


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.


If I have set up my web browser to automatically delete cookies when I close it (or I do this manually) will this affect the performance of the opt out page?


Yes. The opt out page currently works by each business listed setting an opt out ‘cookie’, effectively saying ‘do not do behavioural advertising’. If you delete cookies at the web browser level you will need to revisit the page to set your preference. We are working on a solution to make this more effective and to ensure your preference is permanent. Please note that managing cookies at the web browser level also provides a way for you to safeguard your online privacy.


If I have privacy or ad blocking software installed on my computer will this affect the performance of the opt out page?


It may do although the software itself may provide you with a high level of privacy already. We have a ‘trouble shooting’ checklist may help you or you can send us your feedback.


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.


I’ve heard of an initiative called ‘Do Not Track’: what is it and how does it relate to online behavioural advertising?


‘Do Not Track’ is the name given to an initiative to enhance the privacy settings within the web browser that you use to browse the internet. The initiative is being led by a global standards body called the World Wide Web Consortium (W3C). While the exact details are still being finalised, the advertising industry has already endorsed the idea of Do Not Track for online behavioural advertising. Once the standard is finalised this website will interact with it. The advertising industry is committed to making sure this initiative is interoperable with ‘Do Not Track’ to help consumers make informed choices about whether they want information collected and used for this type of advertising or not.


Do I need to do anything?

Have a quick look at our five top tips.


I wish to make a formal complaint. How do I do this?

Please visit our complaints page.


Who can I contact for further information?

If you have any questions please send us your feedback.