Information Extraction (IE) is a sub-discipline of language engineering, a branch of computer science. It aims to apply methods and technologies from practical computer science (compiler construction, artificial intelligence) to the problem of processing unstructured textual data automatically, with the objective to extract structured knowledge regarding a predefined domain. A typical example is the extraction of information on corporate merger events, whereby instances of the relation MERGE(company1,company2,date) are extracted from online news ("Yesterday, New-York based Foo Inc. announced their acquisition of Bar Corp.").
The significance of Information Extraction is determined by the growing amount of information available in unstructured (i.e., not modeled relationally) form, for instance on the Internet. This knowledge can be made more accessible by means of transformation into relational form.
