ClearCoin is an escrow-type of service that allows safer payment.
Sometimes there is a risk that a buyer will be unhappy with a purchase but the has no recourse because Bitcoin transactions are not reversible. An escrow allows the buyer to send payment to an intermediary and release the funds only at such time the buyer is satisfied with the seller's level of service.
ClearCoin escrow simply acts as a time lock for a bitcoin person to person transaction. After sending payment to escrow, either the escrow can be released and ClearCoin will forward the escrowed amount to the seller, or after the escrow expires (options available are 1 month, 6 months and 1 year expirations), the payment will be returned to the buyer.
When the buyer refuses to release the escrowed amount, the delay in getting those funds returned may be an incentive to try to work things out with the seller. For the seller, there still is the risk that the buyer will have received the goods or service and then still refuse to release payment. ClearCoin does not mediate disputes.