A recent trend in advertising viral marketing. The goal is to convince
viewers to share
1 amusing advertisement by e-mail or social networking, Imagine
that the video is sent to 100 people on day 1. Each person agrees to send the video to
5 people the next day, and to request that each of those people send it to 5 people the
day after they receive it. The number of viewers v(n) is an exponential function of the
number n of days since the video was first shown.