Ask HN: What is the name of this business model?

What is the name of a business model where company generates social good in order to market itself to the public while also selling the same product to private customers?

Think of GitHub - they become known as a free code repository for open source projects gaining fame among the software developers and subsequently selling the same product for money to closed source (private) companies.

It fits under the definition of a freemium model, but is there a more specific term for when the free part is valuable as a social good, not just a free limited version of the same product?