Dove soap and the "Will it Blend" videos have convinced marketers that going viral can be very effective.
But going viral is very difficult, as an excellent article in the Wall St. Journal.
The headline pretty much sums it up: "Trident Finds It Hard to Go Viral: Campaign Based on Fake TV Show Fails to Catch On With the Web-Savvy."
One of the challenges is defining criteria for success. The article discusses some metrics while people involved in the Trident video say it's been successful and others in the industry saying they were not.
That's been one of the problem I've been pointing out for the past year.