From Patti Digh writing at 37Days comes this wonderful video of a crowd in a train station dancing to Do-Ri-Me:
Was this staged?
It seems to have "just happened" until the last couple of dance moves which are so coordinated it must have been "staged".
Was it effective?
I would judge by the faces of the bystanders. Most of whom really were enjoying the performance, taking pictures, etc.
Will this be viral like the Susan Boyle video?
Time will tell. You can help by spreading the word.
If it is good enough, it will be viral. If it is not good enough to go viral, it will still be good.