  In recent years, the study of complex networks has received a lot of
attention. Real systems have gained importance in scientific publications,
despite of an important drawback: the difficulty of retrieving and manage such
great quantity of information. This paper wants to be an introduction to the
construction of spiders and scrapers: specifically, how to program and deploy
safely these kind of software applications. The aim is to show how software can
be prepared to automatically surf the net and retrieve information for the user
with high efficiency and safety.
