NFTX is a platform for creating liquid markets for illiquid Non-Fungible Tokens (NFTs).
Users deposit their NFT into an NFTX vault and mint a fungible ERC20 token (vToken) that represents a claim on a random asset from within the vault. vTokens can also be used to redeem a specific NFT from a vault.
From the full page, this is what the Song A Day vault on NFTX is all about:
The Song A Day vault contains Song A Day NFTs that users have added into the vault. It has an ERC20 Token, $SONG , which is backed 1:1 with the NFTs within the vault. When a new NFT is added to the vault, another ERC20 $SONG token is minted. When someone buys/redeems an Song A Day NFT from the vault, one of the ERC20 $SONG tokens is burned.
Read the whole page on the NFX academy for all the ways you can stake, sell, buy, swap, or even dollar cost average the purchase of a Song A Day NFT.