For perspective, that's >$320k today. For 'switching apps'. It's always kinda crazy to look back and realize how incredibly minute and small programs were back them. Like 'spellcheck' being a project you'd assign half a dozen programmers to or Knuth would write almost a book about.
Who did they sell to for the $50k royalty?
Previously:
Switcher (2004) - https://news.ycombinator.com/item?id=32414661 - Aug 2022 (30 comments)
"Don't argue with me. $100,000 is fair, and you know it." - https://news.ycombinator.com/item?id=1637862 - Aug 2010 (110 comments)
Mac OS gets multi-tasking - https://news.ycombinator.com/item?id=1319308 - May 2010 (7 comments)
For interest "IBM PC Memory Shift software utility 1984" returned no useful hits for the software described that way early on the article.
As a 1980s developer I'm going to guess that's meant to reference Borland's Sidekick which was a seismic revelation for the time.
* https://en.wikipedia.org/wiki/Borland_Sidekick
Or was Memory Shift an actual TSR swapper I just never encountered?