YouTube has recently rolled out messaging feature to the web version. Previously it was only a mobile-only feature.
According to reports, the messaging feature, enables chatting right from www.youtube.com .
The conversations will be accessible from the chat bubble icon placed next to the notifications bell on the upper right corner while the chat history will pop up on the bottom left of the screen.
The feature will enable content to be shared into private conversations using the share button under any YouTube video followed by selecting a contact. It also enables the user to react with hearts to like a video or message in the chat.