We’ve all noticed those ads that seem to follow us around on the internet. For example, you use a search engine to find information about local bike stores. Then you visit a few websites for bicycle gear. Next thing you know, you're checking out the news online, and you see ads for bikes, bike racks, and bike trips. How did they know? It's not magic. It's today’s technology. Tailoring ads to a consumer’s interests is now one of the most popular forms of digital advertising. That’s because it is the most effective way to reach the consumer who may be interested in a company’s product or service. How does it work?Companies offer custom shopping experiences online using technologies like cookies and mobile ad IDs which collect data about the sites you visit and what you buy. That makes it possible to suggest products and services you may like and personalize offers for what you are looking for.From social media sites to search engines, digital advertising companies help brands find out whether you are a likely customer for their products and services. They do so by noting the places you visit while you are browsing the internet on your computer, tablet, or phone. These companies may combine this data about your browsing habits and app usage with what other companies know about you, such as your interest in biking. Marketers look to many online and offline sources, such as the magazines you subscribe to, the social media platforms or the browser you use, or your loyalty cards. Based on many kinds of publicly available information, companies are likely to know your age, whether you are a homeowner or renter, and your estimated income level. If you are not signed into a service or app, this data is not matched to you specifically, but only to the web browser or device you are using. Interest-based advertising (or “IBA”) helps pay for content on the internet so that you can use apps or visit websites for free; it also shows you ads that are more likely to actually be of interest to you. But some folks find the practice off-putting for personal privacy reasons. The digital ad industry took such concerns seriously and created a set of privacy standards that online ad companies need to follow. These standards, the Digital Advertising Alliance’s Self-Regulatory Principles, require companies to be transparent with you about their IBA practices by telling you the kinds of data they collect and how they use that data. These Principles also require companies to give you an easy way to opt out of IBA in case you would rather not get it.Here are some helpful tips about IBA for the privacy-conscious consumer: •\tEvery interest-based ad should have a blue icon in or near the ad. Beyond just marking IBA, the icon provides an easy way to learn more about the company that selected this ad for you and decide whether to opt out. All you need to do is click on the icon! •\tYou can opt out of IBA on your desktop or laptop computer by visiting www.aboutads.info/choices and using the DAA’s WebChoices tool. •\tIf you want to opt-out of IBA on your mobile device (iOS or Android), visit http://youradchoices.com/appchoices and download the AppChoices app. •\tClearing your cookies or resetting your mobile device’s special advertising ID may cause companies to think you are a new visitor to a website or app, but these actions are not the same as opting out. This is because these methods only take place on your device and do not send a signal to companies that you would like to opt out of their interest-based ads.The Better Business Bureau’s Online Interest-Based Advertising Accountability Program monitors companies engaged in IBA. The Accountability Program ensures that these companies are following industry standards by providing consumers with notice and choice about this type of advertising. If you think a company might not be following industry standards about IBA and consumer privacy, follow this link to file a complaint.