Some "elevator pitch" for Radium (combination of documentation and own words of @ganastor aka Michael from Tele):

Radium allows users to obtain a secure blockchain identity, as well as providing file verification and ownership.

Identity verification is designed to provide confidence in user accounts, and prevent scamming from accounts with misleading usernames.

Just like humans have unique fingerprints, digital files also have unique fingerprints called a hash. File hashes are generated by passing a file through a cryptographic hashing function. Using a digital identity, a user can sign a file hash, and create a public, permanent, and time-stamped record in the Radium Blockchain.

This allows filed to be cryptographically signed, and this signature can't be changed or hacked due to being stored in the blockchain.