Who will run the CoinJoin coordinators?

This limitation is not unique to Joinmarket; similar challenges are observed with CoinShuffle and its advanced iteration, CoinShuffle++. Despite improvements, both protocols still depend on a form of coordination, termed a "bulletin board" for CoinShuffle(++), to facilitate communication among participants. This necessity for a coordinator or bulletin board to receive and broadcast messages introduces complexity, particularly in assigning participants to sessions, which remains a significant hurdle in the practical implementation of CoinJoin-based solutions. These issues underline the persistent challenge of coordinating decentralized transactions without sacrificing privacy or efficiency.