Been a while since I've actually used Byteball. Just wondering if there are any use or markets yet for Blackbytes.

I remember there used to be a service which traded Blackbytes for regular GBytes at a 2% ratio or so. Wondering if that still exists.

I think I tried sending Blackbytes in the past but got some error, for some reason they can't be sent like regular Bytes and need to be sent a special way. Is there some tutorial which discusses on how to send these Blackbytes?