Arecent trend in advertising is viral marketing. the goal is to convince viewers to share an 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.