A huge number of web sites appear every day, overcrowding the existing body of medical and non-medical information in the net; Sources are not always reliable and usually covers commercial and propaganda purposes. This may arise an special concern regarding the dissemination of mislead concepts and practices on the response to pandemic Flu.But not everything is negative on this specific matter. An example of this is the possibility of early detection of new cases of Flu, due to the easy access to information regarding clinical symptoms that search engines like Google or Yahoo, provide to the general population. A new online-based method of outbreak surveillance, appear to be a useful tool, an it’ been denominated “infodemiology”. This method allows a real-time monitoring of cases and predicts the expansion of the disease, through continuous and structured analysis of information available on the internet.Another aspect to remark is the quality and promptness of information available on the web, provided by the institutions responsible for controlling infections in the world (e.g World Health Organization), improving the response to a pandemic threat.