A network allows you to group multiple podcasts together. Members of a network can see and manage all podcasts in the network. Members of the network can also add their own podcasts, which in turn gives access to all other members.
Collaborators, on the other hand, apply to a single podcast only. A collaborated user will have access to only the podcasts that they are collaborated on.
If a podcast belongs to a network, users collaborated on that podcast will not have access to the network.
Networks are useful for podcasts that are jointly owned. Keeping them grouped together allows for easy comparison. This is great for teams where all members of the team share access to all podcasts.
A network can only have a single member (the creator of the network), and be used solely to group podcasts together in a useful dashboard.
Adding a collaborator to a podcast is useful to share targeted access. If you own five podcasts, but only want to grant a user access to two of them, adding the user as a collaborator is the perfect way to do that. Collaborators can be used to configure more complicated permissions than the blanket permissions granted by networks.