Could be what I think of as 'traffic stenography' (misplet), a lot of that goes on in the Tor network.You have some indirect method of control in some publicly accessible arena e.g. bus routes, letters to the editor, sequence of songs played on a radio station, seconds between windows updates, misspellings on forum posts... etc.There is always patterns in such things. Thing is, you can hide information in those patterns to send messages. Only those able to do certain traffic analysis are capable of receiving the message.Protip: pretending that such patterns exist could also be an excellent way to turn the enemy into paranoid fruitcakes and waste their time, remember, Russell Crowe in A Beautiful Mind? Something like that :D