From gillette
The Internet has introduced a new way of marketing that does not require targeting your customers, advertising on billboards or magazines. All you’ve got to do now is create something original enough, goofy enough, crazy enough and post it on the Internet, say on YouTube, and then wait for millions of Internet surfers to post it on their blogs, tweet and retweet it, and make it go viral.
Which is what Gillete has done with this ad printed on a strand of hair using an electron microscope. Obviously, no one can see this ad with their naked eyes. But post it on YouTube, publish it on some well-visited sites and soon the whole world is viewing it.
source gizmodo