Comment by mquander
Actually, the main reason I used Nebula was that they advertised a credible-to-me promise that you could download and permanently delete your data upon request. That was some years ago, so I don't know if I would trust them today. But that was their claim, and I have no reason to believe they didn't delete my data.
That's a legal requirement in the EU and many US states. Some of the genetic genealogy companies actually play fast and loose with it though - not the deletion, which I trust, but the data portability and reasons to store PI parts.