Box, for example, started spreading entirely by word-of-mouth, and now has grown big enough to merit a fleet of salespeople calling on would-be customers.
According to Comscore, it's the most visited fitness site with 7 million users (162 million page views in January), but Spark has taken a low-key, word-of-mouth approach compared to its big bucks advertising competitors like Weight Watchers.
Controversy continues to boost the Kathryn Bigelow-directed drama's profile, but great word-of-mouth seems to be playing just as big of a role in "Zero Dark Thirty's" success.
It's also become more common for individual web sites to solicit donations for all sorts of big requests - from supporting the families of Sandy Hook victims to fixing one's mangled mouth.
The project was part of a Street View "refresh" of California that involved a trip down Highway 1 along the Big Sur coast, including the famous Bixby Creek Bridge that spans the mouth of a coast-hugging canyon.