YouTube is expanding its in-app video sharing and messaging feature to the U.S., U.K., Brazil, Singapore, and several U.S. territories, per the availability list on its help page. The rollout, announced in a blog post, lets users 18 and older share videos and chat about them without leaving the YouTube app. It brings back a version of messaging YouTube removed in 2019, when it told users to share videos through other apps. Sharing a YouTube video has usually meant sending a link through a messaging app ever since. This update brings some of that activity back onto the platform. How The Feature Works Messaging on YouTube runs on invites. You send an invite link from the new messaging icon, and the recipient can allow or decline. Per YouTube’s help documentation , invite links expire after seven days. Once connected, people can share long-form videos, Shorts, and live streams, then chat about them in the app. Messages can be unsent, and users can block or report each other.…