For those who want to know the difference between PLATO and NovaNET, it might be interesting to know that at one point they both had the same origin. The original PLATO program was invented by Dr. Donald Bitzer in 1960. It soon became associated with CERL (Computer-based Education Research Laboratory now known as the Engineering Research Laboratory) at the University of Illinois-Urbana-Champaign. Contrary to what others may think, the original word PLATO is an acronym for "Programmed Logic for Automatic Teaching Operations"
This original PLATO program was developed to be accessed through online subscriptions. In 1976, Control Data Corporation received a license to market PLATO systems, the rights to the name PLATO, and the PLATO basic skills and high school level and possible other software. The software was marketed as stand-alone software programs. In that state, I believe, there were little changes or revisions made to the program.
In the meantime, CERL continued to develop and expand the software for the online subscription program. I believe somewhere in the late 1980's, CERL at the University of Illinois, having lost the right to use the name PLATO from CDC (Control Data Corporation), started to use the name NovaNET. In 1987 NovaNET Learning, Inc. marketed the NovaNET program. In 1999, it then continued with the same name under NCS Learning and in 2000 it was acquired by Pearson.
In 1989, TRO (The Roach Organization, Inc.) and two other firms acquired the PLATO software from CDC. In 1992, TRO, Inc. became TRO Learning, Inc. In 2000, the company again changed its name to PLATO Learning, Inc.
I'm still searching for any current connection between NovaNET and CERL. For the more curious, I have since come across an article that chronicles the two programs up to 1993 at this site: http://www.cs.uiuc.edu/whatsnew/newsletter/winter93/plato.html.