  The main information of a webpage is usually mixed between menus,
advertisements, panels, and other not necessarily related information; and it
is often difficult to automatically isolate this information. This is precisely
the objective of content extraction, a research area of widely interest due to
its many applications. Content extraction is useful not only for the final
human user, but it is also frequently used as a preprocessing stage of
different systems that need to extract the main content in a web document to
avoid the treatment and processing of other useless information. Other
interesting application where content extraction is particularly used is
displaying webpages in small screens such as mobile phones or PDAs. In this
work we present a new technique for content extraction that uses the DOM tree
of the webpage to analyze the hierarchical relations of the elements in the
webpage. Thanks to this information, the technique achieves a considerable
recall and precision. Using the DOM structure for content extraction gives us
the benefits of other approaches based on the syntax of the webpage (such as
characters, words and tags), but it also gives us a very precise information
regarding the related components in a block, thus, producing very cohesive
blocks.
