The first case was mentioned by the German news magazine Der Spiegel. They reported about a hidden feature on the German microsite for the BMW 3 Series: just click on one of the girls in the Flash animation and she suddenly walks towards you - until she hits screen ! Nice idea !!
The other Easter Egg is even better: it's hidden in the software of the real car (from Popular Science):
"There's a cheat code in the software running the BMW M3's sequential manual gearbox (SMG): Press the right buttons in the right order and the car will launch you from a stop after revving the engine to 5,000 rpm. But don't look for a how-to in the owners' manual—this feature is undocumented, an inside joke of sorts."If you want to know, if this really got viral, just check out Technorati or Feedster, to see how often the article in Popular Science was quoted in various weblogs around the world.
Looks like it worked, doesn't it ?