Hi all, I'm sure you know this email virus joke ('please follow these steps: 1. send this email to all your contacts / 2. delete all the content of your hard drive'). Here you will be kind to copy-paste the code of this happy flu on your webpage and send the url to your contacts. :) http://www.liafa.jussieu.fr/~prieur/happyflu.html Seriously, what's interesting here is to follow the spread on the map... -- Christophe Prieur, Liafa, University Paris-Diderot user experience research, social networks, graph algorithms