Traditionally, along with the scientific magazines this "dark" literature has been vehicle of diffusion of science. The concept of gray Literature is analized and the conclusion is that the theoreticians do not agree in the limits of gray literature. The new forms of communication through Internet allow the exchange of information almost in real time; this is the greater revolution in relation with the past. Through the distribution lists, news, weblogs, etc., can be made an analysis and interpretation of the information, which generates new knowledge. The characteristics of weblogs study and they are compared with those of gray Literature, establishing common characteristics. But, in Internet a voice has been raised to equip with ISSN weblogs, considering them like publications. Also there is one who considers a journalism form. So, a reflection becomes: It is possible to systematize the phenomenon of weblogs and to consider them like members of gray Literature?