Common law liability is when a person is guilty of committing an act which is known to be wrong and is accepted in general by most people but which has not been ruled on through legal statute. This means that the act itself is not illegal, but the liablity still rests with the person who committed the act.
The basis of common law is fault. This is why common law decisions are binding, but do not result in criminal repercussion such as jail time or other sentencing measures. Common law liability by nature is settled through financial means.