http://u3qwdut6yva3iyewthpkmzyfgmt5f7xzoohktgyrafugxzar7dkcq3yd.onion/ru/blog/item/madeamaze
This decreases the amount of available service funds, so only services with sufficient bitcoin reserves can afford such an approach. For example, if a user sends 120 Bitcoin to a service with a 220 Bitcoin balance, his limit for further use will be reduced to 100 Bitcoin until his funds pass several mixing operations within the service.