I remember that, it used a flat file for database. I believe the misspelling "discus" is correct, it had some kind missplelling.
I would suggest looking getting something new for a variety of reasons, for example if your forum becomes popular the inadequacies will become very apparent quickly. Conversion to something else if you wanted to save all your posts, members etc. becomes a royal PITA when the software is really old/obscure .
phpBB offers free forum software and there is others. If you're looikg for a more simplified look like WW has there is plenty of stripped down themes available or if you know HTML you could create your own.
I was a big-time Discus user back in the early 2000s. With some tweaking, it was very SEO friendly. Then, Discusware did a major "upgrade" that would have changed my URLs and SEO strategy. Instead of implementing the new version, I switched to vBulletin and never looked back. It was an interesting product for low and medium volume forums. One cool feature of the original version was that "forums" and "threads" were kind of similar. You could start a thread within a thread, and in essence users could create new topical forums. That could get messy, too, of course, but it was a great way to identify topics that people wanted to talk about - those topics kept getting posts and would stay near the top of the list.
I didn't find Discus to be too similar to BestBBS, which is unique to WebmasterWorld. BestBBS is far more scalable in terms of handling high posting and reading volume.