Sabotage, bureaucracy, and emoticons: Inside the late ’90s chat wars between Microsoft and AOL, from the perspective of a former Microsoft programmer:

The messenger war was a rush. Coming in each morning to see whether the client still worked with AOL was thrilling. I’d look through reams of protocol messages to figure out what had changed, fix the client, and try to get an update out the same day. I felt that I was in an Olympic showdown with some unnamed developers over at AOL. I had no idea who my adversaries were, but I had been challenged and I wanted to win.

AOL tried different tactics. At one point they seemed to be identifying the Microsoft client because it wasn’t downloading a huge chunk of advertising that the AOL client downloaded. So I changed our client to download it all (and then throw it away). They put in mysterious messages that didn’t seem to affect their client but broke ours because we weren’t expecting them. One day, I came in to see this embedded in a message from the AOL server: “HI. –MARK.” It was a little communication from engineer to engineer, underneath the corporate, media, and PR worlds that were arguing over us. I felt some solidarity with him even though we were on opposing sides.