When an organisation tries to match the ads you see while browsing online with your interests, this is called targeted advertising. It's also called interest-based advertising or online behavioural advertising. Advertising and data collection organisations do this by placing a ‘cookie’ on your computer, smartphone or tablet.
Interest categories, based on the websites you visit, are attached to these cookies and can allow online advertisers to build up a picture of your browsing habits and interests. These interest categories can then be used to deliver ads.
Many ads on websites aren’t placed there by the website you visit, online advertising networks supply them. An online advertising network may deliver ads to many websites and may be able to track your browsing activities across many sites. The website you visit may also have its own analytics tools and trackers running to collect information, such as how many people visit the site, how long they stay, and how they navigated to the website.
Is your privacy protected?
The Privacy Act 1988 applies to personal information, which, broadly speaking, is information that can be used to identify you. The information an online advertiser collects is often not enough to identify you — it might just be general information about your interests and the websites you’ve visited. So an organisation that uses targeted advertising may not need to comply with the rules in the Privacy Act about how personal information is handled.
However, it’s important to remember that new technologies are making it easier for the information that you give when you are online to be combined. This is called data aggregation.
What is a cookie?
A cookie is a small data file stored on your device’s browser. Its purpose is to help a website keep track of your visits and activity.
You will usually find information on cookies and how to manage them under options or settings on your browser. You can choose to see cookies before deleting them and to keep cookies from some websites. Setting your browser to block all cookies may make some websites take longer to load and stop you saving customised settings such as text sizes, location or sign in information.
Different types of cookies
A first-party cookie is sent from a website to your web browser when you visit that site. This is how a website remembers things like your customised settings (such as your location), your shopping cart contents and your sign-in details.
A temporary cookie only lasts for one browsing session (until you close your browser). A persistent cookie remains on your computer after you close your browser and will be sent back to the website each time you visit.
Another type of cookie is the local stored object (LSO), also known as a Flash cookie. You can only get Flash cookies if you have Adobe Flash Player plugin installed in your browser. A Flash cookie can store much more data than a browser cookie and is not affected by the same rules. For example, a browser cookie is confined to a single browser, has an expiry date and is deleted when you clear cookies from your browser. A Flash cookie does none of these things. You need to manage Flash cookies on the Settings page in Adobe Flash Player or in the online Adobe Flash Player Website Storage Settings panel.
Use a web browser’s privacy features
Different web browsers have different settings and features that you can use to help control your personal information online. Common options include deciding whether to accept cookies and how long to allow them to stay on your device. Many browsers allow you to view in private mode, which usually means your browsing history won’t be saved to your device, but it doesn’t mean the browser will automatically block all tracking of your activities online.
Opting out of targeted advertising
Some organisations that deliver targeted advertising give users the options of viewing their profile, editing it or opting out of receiving targeted ads. Choosing to opt out won’t remove advertising from the pages you visit — it means the ads you see won’t be matched to your interests.
You can opt out of Facebook, Google, Twitter or Instagram by looking under its account settings.
You can visit Your Online Choices and do a blanket opt-out for the organisations who signed up to Your Online Choices. When you opt out of receiving targeted ads, this information is usually saved on a cookie. Often this means that if you clear your cookies, you’ll have to opt out again.
Choosing to opt out of receiving targeted ads doesn’t always mean that information about your browsing habits won’t be collected. There are tools available which will help you see which trackers are active on web pages you visit and allow you to block them. For example, Ghostery.