At this very moment, DAML applications run on the DA ledger. Open sourcing the language is the first step in expanding that base. We (yes, I work at DA!) have been working with key ledger providers and will be making additional announcements over time - perhaps starting within the month if all goes well.
So is the idea that it's abstracted from the ledger, basically meaning you have your choice of whether you would run it in some centralized ledger secured within your company or on a more blockchainey distributed ledger on the public internet?