I checked a few sites I found from the list in the sidebar of /r/darknetmarkets. A couple of them allowed paying into their escrow service with Monero, and for vendors to receive Monero, but it looks like they're still fundamentally based on a multisig Bitcoin transaction.
This seems like a mistake to me; I would have expected faster Monero adoption, especially with Bitcoin hitting performance bottlenecks.
yeah, darknetmarkets should have dropped bitcoin completely a while ago
I'm not sure Monero's 2-of-3 multisig is actually merged into production yet, but they have 2-of-2 so thats still a real limitation. Also Monero has and will hit performance bottlenecks very quickly too, cryptonote coins have no layer-2 scaling solution on the roadmap. Although they have had adaptive block sizes from day 1, the block sizes grow very slowly compared to spikes in traffic. The transaction fees would quickly reach unoptimal $ amounts, but the market itself would just require larger deal flow.
This seems like a mistake to me; I would have expected faster Monero adoption, especially with Bitcoin hitting performance bottlenecks.