You don't. But hodhodl doesn't have your info. And holdhodl isn't custodial. But they do get a fee, and that pmt for the fee is a leak, I believe.

So I think there is a way from blockchain analysis to determine that coins withdrawn from coinbase, by customer X, for example, were then traded on hodlhodl -- presumably by X . But x doesn't know you, coinbase doesn't know you, hodlhodl doesn't know you.

But let's say your payment method was bank trsfr. Well, authorities could see X's bank acct transfer, and that you paid $524 to X on the same day X's coins worth $500 were traded on HodlHodl.

But that's generally a little bit more work than what they're going to do unless they're really looking for either you or for X.

So that's why coin joining or other things you can do are still tools to use, if financial privacy is important.