Originally I thought it was basing it on Comnet or Compuserve but after reading these comments, I now think Quantum Link makes more sense. They are doing a good job portraying the various personalities, especially the disfunctional ones.
In the episode where there is a room full of people and it's up on a projection screen -- I looked up the Quantum Link main page online and it seemed to match.
http://toastytech.com/guis/c64gquantumlink.gif That thing -- Ethan O'Toole