Amazon is finally catching up with the online co-watching phenomenon, with a new built-in feature called Watch Party, which lets you sync up reading with loved ones. Watch Party requires an Amazon Prime subscription, not surprisingly, which means you can only use it with other Prime subscribers. However, for those who have it, it opens up a much more social way to watch Amazon Prime movies and TV shows at home in social isolation. A viewer must act as a host, controlling the reading for others. There's also a built-in chat feature, which allows you to communicate via text messages and emojis (the most important part of any movie review). However, only titles included in a Prime subscription are supported, which means that not all movies available for rent or purchase are eligible for sync, likely to prevent one person buying a movie and multiple people. look at it, but it seems like a disappointing constraint. Do you want to start? Just go to a title on Amazon Prime that you want to start watching and click the "Watch Party" button, which should be placed next to "Trailer" and "Watchlist" in the show's description. It is currently rolling out in the United States, with further availability likely in the coming weeks.