A great, short and very pithy post by Broadstuff has really cheered me up, in that they have gathered empirical data on the viral uptake rate and the decay of that rate in a real 'viral meme' (the “25 things” meme on Facebook). The more of this we get, the better we will be able to tune Andrew Chen's excellent little formula, probably using some of the techniques I went through in six parts before (here).
Nice to see marketing catching up with biology.