Yeah. A blockchain is a chain - new stuff is built on top of old, and it grows forever. Ripple's ledger is all relatively up to date information IIRC. It doesn't actually need the chain, because as long as a critical number of nodes agree on a single order of transactions, they can agree that only the first spend of a set is valid if it would otherwise lead to double-spending (which is the main challenge of a distributed currency).

How that agreement is reached in an asynchronous network with possible malicious nodes is the real trick, and at that point I do start getting fuzzy on the details. Byzantine fault tolerance is hard. I think I'm actually going to read the whitepaper (again?), now that I'm thinking about it.

Edit: It's still not. I guess "blockchain" has just become just a marketing term at this point. The current crypto market is dumb even if crypto isn't.