It's worth noting that third-party extensions enabled this functionality previously, but that comes with its own issues. Users have trouble trusting Microsoft, let alone a random developer that's processing every single webpage they visit.
Microsoft's extension should garner a little more trust while bringing data to other platforms. The extension will work with Microsoft Launcher on Android to display the data there.
In its announcement, the company promised further expansions of the feature, including more apps.
“As we move into planning for future development, we are focusing on yet another Insider request: add support for more apps in Timeline,” said Microsoft. “Browser support was especially high on our Insider's wish list — which lead the recent introduction of our Chrome extension. Now, Timeline can now bring together even more activities.”
Unfortunately, our testing did reveal some issues with the extension. For some users, it appears to prompt an account sign-in infinitely. The inability to log into the account sadly means no Chrome activity being displayed in Windows.
Still, it's early days, and it's likely these bugs will be ironed out soon. Long-term, this should prove a major upgrade for those that rely on the feature.
You can grab Web Activities from the Google Chrome Web Store.