It was definitely ahead of its time! Not really sure why it faded away, I guess pressure from Steam (pun intended), and games moving to private in-game server browsers? Along with many other options for voice chat.
It was very feature-rich. Literally everything discord offeres, but better implemented, and every feature was customizable - the in-game overlay being the one I remember most fondly. In addition to a VOIP indicator like discord has, it had a text-chat overlay too that my guild used a lot. We were spread out over multiple games, but we all had one unified in-game guild chat thanks to Xfire. You could resize and reposition everything in the overlay, and could set a keybind to toggle whether your mouse and such could interact with the chat windows or just click through it to interact with the game. It was clean as fuck.
VOIP quality was outstanding. UI in general was customizable and also clean as fuck.
It had a built in screen recorder.
Everything was intuitive to use and easy to use.
It was just really, REALLY high quality all around.
Agreed. Cutesy emotes are great when you aren't trying to concentrate on multiple other things at the same time. When I'm mid-game the only chat I read needs to be static and non-moving.