As Emily Moxley, Google’s director of product management for this project, told me, any video on the web is eligible for inclusion, though Google may not have a preview for some of the newest videos available yet because it takes the servers a bit of time to build the previews.

A thumbnail isn’t going to give you a lot of information about what the actual video is going to look like, after all.

That’s because the first six seconds of any given video aren’t usually the most representative ones.

So Google’s algorithm actually analyzes the whole video and then decides which six-second clip to pick.

While the team didn’t want to delve into the details of how this algorithm decides what to show, Google product manager Prashant Baheti told me that the algorithm looks at what’s in the different scenes in a video, where those scenes start and end, and which scenes best represent the video.

Unlike the previously launched Featured Snippet, which directly links you to the relevant answer to one of your questions in a video, the snippets are always the same.

If you want, you can enable video previews on mobile networks, too, or even completely opt out of them in the settings for both the Google app and Google Chrome for Android.