When I was in high school, I played a Chinese MMORPG called Perfect World (North American version: Perfect World International). I created a guild with the aim of becoming one of the top guilds in the newly created server (we did). We did what competitive guilds do, bought a server for Ventrilo, a voice chatting program designed for large groups of people. Through Ventrilo and PWI, I became really close friends with several guildmates to the point where we even shared our account info (lol yes we did, trust was there) to help each other out and stuff. We played together for a couple of years, but then quit the game because it was getting unbalanced and more pay to win. Although we quit, we still kept in contact due to our mutual interest in games, but that eventually quieted down. Fast forward a couple years later, one of the friends I made actually flew from Texas to New York to give me and a couple of other friends who lived in the area a visit. It was awesome.
tl;dr: Friendships can be made through games.