Elder millennial, here. One of the weird things about the 90s was cereal boxes marketed to little bastards like me at the time would often have some kind of toy included in it.
PC gaming was kind of in its infancy and growing rapidly in popularity, so eventually the inevitable happed: a cereal company promoted their cereal by shoving a fucking CD into it, that little bastards like me lost their shit over, installed, and played the snot out of.
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.