From the white paper:

Since we do not know if a user has already confessed their sin, TetzelCoin requires a user to confess their sin to a priest-like smart contract in addition to simply paying it money for absolution. In return, users are given a token of their forgiveness in the form of SIN tokens, an ERC20-compatible cryptocurrency hosted on the Ethereum blockchain. The amount of SIN tokens each user receives is directly proportional to how much money is given, requiring users to balance speculation-driven profit motives with the guilt they feel for their sin. The confession and the amount of SIN tokens that resulted from the transaction are recorded in the blockchain and displayed in a table of sins that anyone can view.

(http://www.autoadmit.com/thread.php?thread_id=3771005&forum_id=2#34498024)