The length and staying power of the recent market rally says something about how crowds work, and why the majority of traders are often wrong at turning points in the market. 
The following video makes the same point, a different way. 

This video was filmed during a live taping
of Oprah. It shows the Black-Eyed Peas,
performing "I Gotta Feeling". It starts with a lone dancer (and I suspect some of it was planned). Yet, it
is fascinating to watch what happens when other people feel the urge to
get in on the fun … and it doesn't take long until the animal spirits spread through the mob.

Pretty cool … 

Here is the original version of that music video.

Related Info.

• Here is a link to the band's website.
• Here is a link to other Black-Eyed Pea Videos.
• Here is a site that has some song samples.