This approach is propably fine for small one-off transactions, but: * Anonymous cash is difficult and illegal to scale. * 'private sites' can not be trusted (

This approach is propably fine for small one-off transactions, but: * Anonymous cash is difficult and illegal to scale. * 'private sites' can not be trusted (they will be subpoenaed, hacked, wiretapped, etc.). * Sellers will learn your identity, and can not be trusted. * You or the seller may be followed.