https://www.gamespot.com/articles/new-steam-chat-features-now-available-for-everyone/1100-6460720/

Steam has updated with revised chat features. The revised functionality was announced last month and has been available in beta, but with the recent update it's become available to all users. It includes new grouping features, a Favorites tag, and more details on what your friends are up to.

The big Chat Update lets you set a handful of friends in a Favorites bar at the top of your list so you can always see what they're up to at a glance. Friends will also automatically be grouped by game and by party, making it easier to jump in and play with them. The friends menu will show more specific detail about what exactly your friends are doing in a game, too. Finally, group chats can be pulled together more easily.