My colleague Liudas sent me a link to this social marketing campaign last week:
The big shame is that whoever posted it on YouTube blew the reveal by telling you what it was about in the title. You figure the spot out halfway through.
Surprise endings are a great way to make a strong first impression on an audience, but only if you can keep the ending under wraps.
This one, from a couple of years ago, was effective not because the topic was hidden, but it had a good ending I didn't expect:
Fortunately, it didn't lend itself to someone calling it the "meth ad where the dude is robbing himself" ad.
This next one is for a commercial product, but a responsible one. (Plus, it won at Cannes a couple years back.) Check out the good use of misdirection:
Sorry about the poor quality; it was the only upload without a give-away title, like this one (in English):
The moral of the story? If you're hoping to spread the viral joy of a great surprise spot, don't put spoilers in the title or tags! Sure, you may limit searchability, but you only get one chance to make an awesome first impression.