Even if Github doesn’t end up being a typical “social network”, this still allows Microsoft to push out the competition (Gitlab, Bitbucket) and become the de facto developer workbench in the industry. MS already released a hit with VSCode and won back a lot of street cred with developers who moved over from Atom/Sublime/etc. Having free private repos just makes sense in order to seal the deal with consumers, and migrate them over to the MS developer ecosystem. It’s very Google-esque. Github was already the ‘Chrome’ of the code repo world, and now it has a chance to pull further ahead. This is what MS wants, because now there is even less reason for users to look to migrate if what they used to have to pay for is now free.