Ravencoin is a protocol based on a fork of the Bitcoin code. RVN is the token. The parameters of Bitcoin were improved for faster confirmations (1 minute), a slightly larger block size (2 MB), and Ravencoin is its own independent decentralized network.
The protocol was extended in Nov 2018 to add features specifically focused on allowing anyone to quickly and easily create their own token. This can be thought of as an easier-to-use ERC-20. Every token created has a guaranteed unique name, as the DNS-like name resolver is built into the protocol.
The protocol also includes the ability to immutably include meta-data, messages, and memos. Meta-data typically describes the purpose or intent of user-created tokens. Messages are linked to the issuer of a user-created token. Memos include data about a transaction. All of these use IPFS and can include any size or type of data.
Ravencoin is its own blockchain. It does not include smart contracts, and the blockchain has been operating 24x7x365 since its fair launch on Jan 3rd 2018. It is proof-of-work. RVN was never an ICO, and never pre-mined.