Social Media gives you a distribution platform. Then you pray that people will promote you. Think about a movie, say, the fouth movie in a series based on a ride a Disneyland... you have brand recogintion, star power, and a strong franchise. But do you just go out front of the studio and mention to a few folks walking by, "Psst -- Johnny Depp is wearing eye makeup and a bandana again... tell your friends!"
Nope, you buy every surface you can from the sides of busses, to cups that cola comes in at fast food markets. You put it on TV, you send your stars out to talk to Regis, the View, the Soup and anyone else with Distribution. You don't rely on word of mouth.
But there's this mystical cloud around the phrase "social media" -- call it "word of mouth" and no one gives your campaign any credence, but that's what we're talking about. Sure, you're hoping for bubonic plague "word of mouth" but most campaigns are the common cold.
I guess my curmudgeon gene is working extra on this because I hate magic words. Hoping that your campaign is great is one thing, but advertising and promotion has always been about stacking the deck in your favor. You don't just hope that people will pass your product along. That went out with... hell, probably the plague itself. We're just too damn cynical to promote for you.
So, next time you have a great "Social Media" campaign make sure you have a promotion campaign, not just a wish and a prayer...