  The information available on web pages mostly contains semi-structured text
documents which are represented either in XML, or HTML, or XHTML format that
lacks formatted document structure. The document does not discriminate between
the text and the schema that represent the text. Also the amount of structure
used to represent the text depends on the purpose and size of text document. No
semantic is applied to semi-structured documents. This requires extracting core
contents of text document to analyse words or sentences to generate useful
knowledge. This paper discusses several techniques and approaches useful for
extracting core content from semi-structured text documents and their merits
and demerits
