Improvements include a simplified "favorites" list that will pin certain friends to the top, an expanded detail set for what each friend is playing and where they are in the game (for instance, sitting on the main menu or facing off in deathmatch), as well as organisational changes, such as grouping friends by the game they're now playing or the party they're in.
Valve has released a brand new chat system for Steam, with a bevy of new features including a customizable (and prettier) friends list, group chat options, more seamless voice chatting, an invisible mode, shareable friend request links, and more. For those of you who still remember Myspace, the new friends list will also let you designate some friends as "favorites", so get ready to compete for that coveted status.
Your browser does not support video. These groups can be made permanent by saving them with a custom name and thumbnail.
Valve has built a fancy new page that describes all the new features, which can be found here. It's not clear if this means other Valve titles won't be available in the region yet, or what that means for the wider library of games on Steam, but it seems likely that in time many of them will be released there.
Valve has also urged beta users to report any bugs they find, over here.
"As a result, voice chat uses high quality Opus encoding, voice traffic is encrypted, and all traffic is sent through Steam servers rather than directly to peers", it explained.