Moding is a slang expression that is derived from the verb "modify". The term can refer to the act of modifying a piece of hardware or software to perform a function not originally conceived or intended by the designer. The term modding is often used within the Open Source software movement and within the computer game community, particularly in regard to creating new or altered content and sharing that via the web. It may also be applied to the overclocking of computers in order to increase the frequency at the which the CPU operates. Case modding is also a popular activity amongst many computer enthusiasts which involves the customization of a computer chassis or the installation of water cooling technology. In connection with automobiles, modding often refers to engine tuning, remapping of a vehicles Engine Control Unit or customization the bodywork. Modding can also refer to the act of graphically modifying photography including pornography.