Universa Network is the worldwide network of Universa nodes, providing the functionality of distributed and decentralized registration and validation of smart contracts, and storing the validation data in decentralized manner with the means of Universa Blockchain technology.
In most cases, it is only the fact of validation (of some smart contract) which is stored by the network, not the data of the smart contract itself. The network is publicly available, with the “read” operations (to check if some smart contract is valid) being completely free, and the “write” operations (to register the fact of validity of some smart contract or its revision, or to revoke it) requires you to consume some amount of U – and U is kept in smart contracts too! –, which can be purchased for UTN tokens only (which are, again, smart-contract-stored).
You can check the actual status of Universa Network using the Universa Network Scanner.