Sharon Callahan

The trend is strong, bold ideas that travel across cultures.

You remember it well: that day back in the late 1990s, when your brand's Web site first went live. It looked great at the time, and you were so proud to have entered the Internet Age.

Once you get past the Disney allusion, it's easy to see the appeal of the idea that everyone in the world is linked by a short chain of social acquaintances. This "small-world phenomenon" was first advanced four decades ago by social psychologist Stanley Milgram, whose groundbreaking work includes the theory that there are only six links, or acquaintances, between any two randomly selected Americans. Popularized as "six degrees of separation," this notion has been transformed by the digital revolution into a buzzing, booming hyperreality beyond anything even the radical Milgram could have imagined.

Companies used to promote their programs by passing along invitations to physicians through reps or in the mail. But times have changed. There is now a new universe of ways to inform doctors about med ed events.