How efficient can Viral Marketing be ?

When I try to sell viral marketing projects, I always avoid the word "cheap", because when a client hears "cheap", he tends to understand "free". And viral marketing certainly isn't free. But very often it's extremely efficient !

Here are two nice tidbits that show, how efficient it can be, when it is successful:
  • BMW Films: the brilliant film clips from BMW Films were downloaded 67 million times. Because of this success BMW was able to reduce the US ad budget by 40%, while keeping sales at a steady level.

  • Subservient Chicken: the budget to build the subservient chicken site was about 15.000 US dollars. How many hits did Burger King get for that ? 396 millions !
Okay, okay... I know... just anecdotal evidence... and the success of any viral marketing campaign is hard to predict. But then, how predictable is the success of any conventional campaign ? I mean really !?

Btw, I got these numbers from the Culture Buzz Blog of Emmanuel Vivier and he overheard them at this strange little conference, where apparently not everyone felt welcome !? Does anyone here attended this event ? If so, how was it ??

(via Bernd Röthlingshoefer)