Use a Shared Storage to determine what creative a user sees across sites.
The Shared Storage API is a Privacy Sandbox proposal for general purpose, cross-site storage, which supports many possible use cases. One such example is creative rotation, which is available to test in Chrome 104.0.5086.0 and later.
With creative rotation, you can store data, such as creative ID, view counts, and user interaction, to determine which creative users' see across different sites.
Run a Shared Storage worklet to select a URL from a provided list, based on the stored data, and then render that creative in a fenced frame. This can be used to select new ads or other content.
Try creative rotation
To experiment with creative rotation with Shared Storage, confirm you're using Chrome 104.0.5086.0 or later. Enable all the Ad privacy APIs under chrome://settings/adPrivacy
.
You can also enable Shared Storage with the --enable-features=PrivacySandboxAdsAPIsOverride,OverridePrivacySandboxSettingsLocalTesting,SharedStorageAPI,FencedFrames
flag in the command line.
Experiment with code samples
An advertiser or a content producer may want to apply different strategies to a campaign, and rotate the contents or creatives to increase effectiveness. Shared storage can be used to run different rotation strategies, such as sequential rotation and evenly-distributed rotation, across different sites.
In this example:
creative-rotation.js
is embedded in a frame. This script sets which ads are the most important ( weight), and calls to the worklet to determine which content should be displayed.creative-rotation-worklet.js
is the shared storage worklet that determines the weighted distribution for the contents and returns which should be displayed.
// Ad config with the URL of the content, a probability weight for rotation, and the clickthrough rate.
const DEMO_CONTENT_CONFIG = [
{
url: 'https://your-server.example/contents/content-1.html',
weight: 0.7,
},
{
url: 'https://your-server.example/contents/content-2.html',
weight: 0.2,
},
{
url: 'https://your-server.example/contents/content-3.html',
weight: 0.1,
},
];
// Set the mode to sequential and set the starting index to 0.
async function seedStorage() {
await window.sharedStorage.set('content-rotation-mode', 'sequential', {
ignoreIfPresent: true,
});
await window.sharedStorage.set('content-rotation-index', 0, {
ignoreIfPresent: true,
});
}
async function injectAd() {
// Load the worklet module
await window.sharedStorage.worklet.addModule('content-rotation-worklet.js');
// Initially set the storage to sequential mode for the demo
seedStorage();
// Run the URL selection operation to determine the next content rendered.
const urls = DEMO_CONTENT_CONFIG.map(({ url }) => ({ url }));
const fencedFrameConfig = await window.sharedStorage.selectURL('content-rotation', urls, {
data: DEMO_CONTENT_CONFIG,
resolveToConfig: true
});
// Render the opaque URL into a fenced frame
document.getElementById('content-slot').config = fencedFrameConfig;
}
injectAd();
class SelectURLOperation {
async run(urls, data) {
// Read the rotation mode from Shared Storage
const rotationMode = await sharedStorage.get('content-rotation-mode');
// Generate a random number to be used for rotation
const randomNumber = Math.random();
let index;
switch (rotationMode) {
/**
* Sequential rotation
* - Rotates the contents in order
* - Example: A -> B -> C -> A ...
*/
case 'sequential':
const currentIndex = await sharedStorage.get('creative-rotation-index');
index = parseInt(currentIndex, 10);
const nextIndex = (index + 1) % urls.length;
await sharedStorage.set('content-rotation-index', nextIndex);
break;
/**
* Weighted rotation
* - Rotates the contentswith weighted probability
* - Example: A=70% / B=20% / C=10%
*/
case 'weighted-distribution':
// Sum the weights cumulatively, and find the first URL where the
// sum exceeds the random number. The array is sorted in
// descending order first.
let weightSum = 0;
const { url } = data
.sort((a, b) => b.weight - a.weight)
.find(({ weight }) => {
weightSum += weight;
return weightSum > randomNumber;
});
index = urls.indexOf(url);
break;
default:
index = 0;
}
return index;
}
}
register('content-rotation', SelectURLOperation);
使用场景
以上只是共享存储空间的一部分用例。我们将 我们会继续添加样本, 获取反馈 并发现新的应用场景
内容选择
在以下位置选择和显示不同网站上的不同内容: 围栏框架 共享存储空间这些用例的输出门控是网址选择。
- 广告素材轮播: 存储广告素材 ID、观看次数和用户互动等数据,以确定哪个广告素材在不同网站上的呈现效果
- A/B 测试: 您可以将用户分配到实验组,然后将该组存储在共享存储空间中,以便跨网站访问。
- 自定义用户体验: 根据用户的注册状态或其他用户状态共享自定义内容和号召性用语
生成摘要报告
通过共享存储空间收集信息,并生成杂乱的汇总摘要报告。这些用例的输出门控是 Private Aggregation API。
- 唯一身份用户覆盖面衡量: 许多内容制作者和广告客户都想知道 人查看了他们的内容。使用共享存储空间记录用户首次访问 用户看过您的广告、嵌入式视频或发布内容,并防止重复 统计不同网站上的同一用户然后,您可以使用 Private Aggregation API 输出覆盖面的摘要报告。
- 受众特征衡量: 内容制作者通常希望了解其网站的受众特征 受众群体。您可以使用共享存储空间来记录 背景信息(例如您的第一方网站),并使用汇总的数据 以便在其他许多网站(例如嵌入式内容)中生成此报告。
- K+ 频次衡量: 有时也称为“有效频次”通常会有一个 用户会认出或回想某些内容(通常在 广告观看情境)。您可以使用共享存储空间生成报告 的唯一身份用户中,特定内容至少浏览了 K 次。
Engage and share feedback
The Shared Storage proposal is under active discussion and subject to change in the future. If you try this API and have feedback, we'd love to hear it.
- GitHub: Read the proposal, reach whitepaper, raise questions and participate in discussion.
- Shared Storage API announcements: Join or view past announcements on our mailing list
- Developer support: Ask questions and join discussions on the Privacy Sandbox Developer Support repo.