The situation really is complicated if you are committed to the constraint of keeping Octave free. Sidekiq pro is just selling non-free software. It's not just

The situation really is complicated if you are committed to the constraint of keeping Octave free. Sidekiq pro is just selling non-free software. It's not just the right to send email. My second idea was to move to an open core model: hold back more complex or enterprise-specific features from the OSS version, sell those features as an "expansion pack" on top of Sidekiq. Thus, Sidekiq Pro was born. This proved to be popular and forms my business today. https://www.indiehackers.com/businesses/sidekiq?utm_source=newsletter&utm_campaign=interview-promotion&utm_medium=email&utm_source=Indie+Hackers+Newsletter&utm_campaign=ec2594295f-EMAIL_CAMPAIGN_2016_11_10&utm_medium=email&utm_term=0_43062afaa5-ec2594295f-118903173 https://www.indiehackers.com/businesses/sidekiq?utm_source=n... I can't tell about handsontable, but it looks like again it's just plain ol' non-free software, although they do seem to let you look at the source code under what sounds like a restrictive license. pfsense also seems to sell a lot more than just an ebook. They sell backups, what sounds like another non-free addon "plus many more features". Maybe most people don't use any of that extra stuff? None of this sounds like it's just a matter of selling stooge licenses, and the sidekiq guy even said that selling stooge licenses didn't bring in any noticeable revenue.