SaaS is a good example of the difference between free software and open source. If some software is freely licensed but still a closed platform dependent on a p

SaaS is a good example of the difference between free software and open source. If some software is freely licensed but still a closed platform dependent on a particular client implementation and server provider (e.g. the web apps the article describes, Signal/Telegram/etc), that thing is nonfree despite being open source.