With each new URL you could store the previous ID and use that to build out a chain. It might be fairly expensive to do that dynamically, but there's no reason

With each new URL you could store the previous ID and use that to build out a chain. It might be fairly expensive to do that dynamically, but there's no reason you couldn't serialize all of the previous IDs in a single column. IMHO POSTing is fine, but you definitely want to wait a couple seconds each time.