 Fledge is part of the Privacy Sandbox, a series of proposals to satisfy cross-site use cases without third-party cookies or other tracking mechanisms. Fledge is intended to support advertisers who would like to build up a group of people they want to show an ad to and then later target an ad at that whole group without being able to learn any person's browsing behaviour. Now, one example where an advertiser might want to do this is called remarketing, and that's a way to connect with people who previously interacted with your website. Now, for example, you know, if you look at running shoes on an online shoe store, but don't make a purchase, the store might want you to see an ad when they have a special offer on running shoes. So why do we need Fledge? Well, understanding user interests can result in more relevant ads than simply choosing ads based on site content, that's contextual targeting, or by using information about the user, in other words, first-party data targeting. Now, traditionally, ad platforms have learned about user interests by tracking their behaviour across sites. What we need is a way to present users with relevant ads without cross-site tracking. Now, Fledge does this by enabling on-device auctions by the browser to choose relevant ads based on websites the user has previously visited. With Fledge, the user's browser, not the advertiser or ad tech platform, holds information about what the advertiser thinks a person is interested in. When the user visits a publisher site, a site that displays ads, their browser combines user data, ad buyer seller data, and business logic to conduct an auction to select an ad on the user's device rather than sharing data with a third party. Websites the person visits and the ad networks those sites use cannot learn about their visitor's ad interests. Ad selection is done on the user's browser. Fledge keeps your interests and your browsing activity private. Now, in this example, the advertiser, the shoe store, doesn't learn what pages you're viewing and the ad publisher, the news site, doesn't learn about your interest in running shoes. So how does Fledge work? Well, let's see an example from start to finish. I will show some JavaScript here, but, you know, if you're not a coder, well, like, don't worry, you should still be able to follow along. Now, one caveat here, the outline described corresponds to the current Fledge proposal. The specifics of how Fledge is designed and implemented may evolve, adding to, you know, origin trial testing, API development, and other factors. Anyway, in this example, a user visits a page on a site that wants to advertise its products, such as the online shoe store I mentioned before. The advertiser's site, or the ad tag it uses, asks the user's browser to join an ad interest group by calling the JavaScript function join ad interest group, passing data, including information about ads relevant to the user's browsing, along with the ad platform host name and URLs to access bidding logic and bidding signals. Now, later on, the user visits a site that displays ads, such as a news publisher, and the user's browser runs an auction to choose an ad. Now, the seller in this auction might be the site itself or a third party acting on its behalf, such as a supply side ad platform. The buyers are third parties bidding for the site's ad inventory, that's space where ads can be displayed, such as demand side platforms acting on behalf of advertisers. The seller in this ad auction has three jobs. Firstly, choose which buyers can participate and choose which bid is most desirable based on each bid's price and some other metadata. And finally, report the auction outcome. Now, the seller initiates the ad auction by calling run ad auction with data, including the host name of the seller, signals from buyers and the seller, and a URL for auction decision logic. The auction returns data about the winning ad, and the data cannot be accessed by the publisher's site except to render the ad in a fenced frame. And finally, the ad is displayed. So, that's Fledge in a nutshell. To find out more, take a look at the article here. We have a demo that shows a simple example of using Fledge to join an ad interest group and then initiate an on-device auction. If you have comments or feedback on the API, you can create an issue on the API explainer on GitHub. And you can track implementations of all the Privacy Sandbox APIs on this status page. So, thanks for watching. See you soon. And don't forget to check out our other Privacy Sandbox videos in this series.