What about Excalibur&#x2F;XYZ? That was a home-grown chat running on Dartmouth mainframe computers in the 80&#x27;s&#x2F;early 90&#x27;s. We users of XYZ were considered degenerates by the campus community at large, until a MacOS GUI chat app gained widespread popularity. Does anyone remember what that was called? I think it came with Blitzmail, which was the home grown email GUI on MacOS.