Simply put, it is a curated network of users of a private blockchain, invited by the creator of the network. A common application would be a company supply chain, a company test network for QA'ing those smart contracts your building, a group of investors, or anything, really, where you'd like to restrict and control the membership of the blockchain network.
Once you get the invite and confirm it by clicking on the link in the email, you'll be a member of that network and can add a node to connect to it.
You can also create your own organization/network or launch public nodes to bitcoin, Ethereum, Stellar and Aion. In short, you'll have access to the entire Blockdaemon universe of blockchain participation.
You can be a member of multiple organizations and can manage that from the drop-down list of networks.
Just select your organization, or <Personal>, and then you can spin up a node specific to the selected org.
Spinning up a node:
More questions? Come chat with us live (west coast hours) or drop us a note at firstname.lastname@example.org