"Free" is a very misleading term when it comes to social media platforms. Users of social media voluntarily become the product in exchange for being able to use the "free" things that social media companies make available to them.
I would rather pay Invision for the continued evolution of IPBoard, and pay extra for premium features that go above and beyond what the basic platform provides, than have Invision incorporate Facebook-esque marketing algorithms into the software and monetize my community's members for Invision's gain.