FAQs

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 online behavioural advertising be directed at children?

The IAB’s Good Practice Principles specify that no company engaged in online behavioural advertising (that has agreed to abide by the Principles) shall create or sell a segment intended for the sole purpose of behaviourally targeting children they know to be under the age of 13 years.

What are the IAB Good Practice Principles and how are they relevant to me?

The IAB’s Good Practice Principles are guidelines for businesses collecting and using online information for behavioural advertising. They are based upon three core commitments: clear notice that data collection and use in happening, a choice as to whether you want to decline or opt out and education to help internet users to better understand the practice. See here for more helpful information. The IAB and its members are committed to keeping these Principles under review to ensure they keep up with changing technology and evolving commercial practices.

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

Companies that sign up and commit to the Principles have six months to comply. They will do this by self-certifying their compliance to the IAB and this will be independently verified by an independent third party body. Companies can only self-certify their compliance if they have live commercial services in the UK. Initial signatory businesses have now completed this process.

New signatories continue to have their compliance independently reviewed. However, the IAB (and other EU bodies) is developing a Framework for behavioural advertising for all European markets, building upon the UK’s good practice work. Similar to the UK work, the EU Framework will introduce a pan-European compliance system and businesses already complying with the UK’s Good Practice Principles will be involved in this system. Further details will be available on this site in due course.

Phorm has signed the Good Practice Principles: why hasn’t the company self-certified?

Phorm does not currently offer a live commercial service in the UK, which the Good Practice Principles require. For any further enquiries specifically about Phorm please contact gppfeedback@phorm.com.

What about potentially sensitive information?

Signatories to the IAB’s Good Practice Principles recognise that some interest segments are sensitive in some contexts. It can be very difficult to determine what those contexts are. Signatories have committed to exercising careful judgement and to engaging in a wider discussion with stakeholders, including advertisers and the Information Commissioner’s Office (the UK data protection regulator) about what appropriate practices may be.

In line with data protection law, you need to give your explicit consent for anyone to use sensitive personal data about you.

Will any software be downloaded on my computer?

No.

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.

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.

Businesses signed up to and complying with the IAB’s Good Practice Principles do not use flash cookies to collect data for online behavioural advertising purposes. Signatories to the IAB’s Good Practice Principles do not currently believe flash cookies permit the level of transparency and control for consumers required of technologies used to collect information for behavioural advertising. They should therefore not be used for this purpose until such a time as they provide the same level of transparency and control for consumers as currently exist in browser features for standard HTML cookies. It should be noted that flash cookies can serve useful purposes apart from behavioural advertising data collection that do not impact consumer privacy in the same way, and for this reason the IAB‘s guidance on this point is limited to behavioural advertising policy only.

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 Privacy and Electronic Communications (EC Directive) Regulations 2003.

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 obafeedback@iabeurope.eu