What is data scraping?

Data scraping is a technique by which a code retrieves data from human-understandable output originated from another program and is most often produced either to interface to a legacy system, which has no other tool which is suitable with current hardware or to interface to an external system which does not provide a convenient API. On the other hand, the supervisor of the third-party system will see screen scraping as undesired, due to causes such as increased system load, loss of advertisement revenue, or loss of control of information content.