Yes we haven't been very vocal about it yet because it's not yet part of a go-ipfs release -- it'll be in the next release, go-ipfs v0.4.5. Note on the name: f

Yes we haven't been very vocal about it yet because it's not yet part of a go-ipfs release -- it'll be in the next release, go-ipfs v0.4.5. Note on the name: floodsub is one specific implementation of pubsub. There are many ways to do pubsub, and we chose to go with a naive and simple flooding implementation for now. In the future there will be more, and you'll be able to use different implementations simultaneously.