[mv4]

I think the parent comment was referencing "wash trades", where you trade between your own accounts to create an illusion of active trading (or movement up or down - whatever your objective may be).

Currently this is very easy to do. Such trades are local to the exchange, so they don't register on the blockchain. If you execute them as "maker" (limit) orders, there aren't any fees either. So you can fake significant market activity for free.