Another company that came to mind while reading the article is Shopify. While their core business is eCommerce, they have open sourced some of the major components of their system while still keeping the app that glues them together proprietary.
Some notable mentions:
Active Merchant (payment processing library)
Active Fulfillment (external fulfillment for Amazon/Shipwire/Webgistix)
Active Shipping (shipping carrier integration)
Delayed Job (job queue)
Obviously there is a lot more work that goes into making a product as polished as Shopify, but they have released a large amount of core domain knowledge for other people to use and improve upon. While someone might be able to come along and use the same components to create a competitor, they still win in the end by having more people contribute.
Some notable mentions: Active Merchant (payment processing library) Active Fulfillment (external fulfillment for Amazon/Shipwire/Webgistix) Active Shipping (shipping carrier integration) Delayed Job (job queue)
Obviously there is a lot more work that goes into making a product as polished as Shopify, but they have released a large amount of core domain knowledge for other people to use and improve upon. While someone might be able to come along and use the same components to create a competitor, they still win in the end by having more people contribute.