In common usage, to deface something refers to marking or removing the part of an object (especially images, be they on the page, in illustrative art or as a sculpture) designed to hold the viewers' attention. Example acts of defacement could include scoring a book cover with a blade, splashing paint over a painting in a gallery, or smashing the nose of a sculpted bust. Iconoclasm led to the defacement of many religious artworks.
In computing, website defacement is usually the substitution of the original home page by a system cracker. Defacement is generally meant as a kind of electronic graffiti, although recently it has become a means to spread messages by politically motivated "cyber protesters" or hacktivists.
Religious and government sites are regularly targeted by hackers in order to display political or religious beliefs, whilst defacing the views and beliefs of others. Disturbing images and offensive phrases might be displayed in the process, as well as a signature of sorts, to show who was responsible for the defacement. Websites are not only defaced for political reasons, many defacers do it just for the thrill. For example, there are online contests in which hackers are awarded points for defacing the largest number of web sites in a specified amount of time. Corporations are also targeted more often than other sites on the Internet and they often seek to take measures to protect themselves from defacement or hacking in general. Web sites represent the image of a company or organisation and these are therefore suffer significant losses due to defacement. Visitors may lose faith in sites that cannot promise security and will become wary of performing online transactions. After defacement, sites have to be shut down for repairs, sometimes for an extended period of time, causing expenses and loss of profit and value.