There are lots of places to get involved with platform co-ops and related movements.
The Platform Co-op discussion list is a great place to start. Run by our friends from Platform.coop the list has lively chat and a good community focused specifically on platform co-ops.
The Cooperative Technologists forum is another excellent and active community, based in the UK. CoTech is a network of technology focused digital cooperatives who are “building a tech industry that’s better for its workers and customers through co-operation, democracy and worker ownership.” This is an open community discussion forum, you don’t have to be a member of a coop to join but you do need to support the cooperative values and principles and have an interest in technology.
The Open App Ecosystem group on Loomio is a neutral group to talk about how we can build a suite of interoperable, open source tools which support transparent, democratic, and decentralized organizing. It’s not a working group, but is a resource where all creators can gather to exchange information about their projects and practices.