Last week, we told you about the billboards popping up around Greenville, SC, to promote something called “Greenville Jetpack Rentals,” promising area residents that they could soon be zipping around town in the way all those futurists had predicted we would back in 1958. But as we predicted, this was just cruel viral marketing, and for something nowhere near as cool as jetpacks.

Some had predicted it would be new high-speed citywide WiFi network. Others had suggested it would be an electric car-share company. Nope, it’s significantly more low-tech than that. These “jetpacks” were a teaser for… a bike-share service.

Now we have nothing against bike-sharing. It’s a great idea. But you don’t promise jetpacks and then show up with bikes.

One area resident tells FOX Carolina that these ads were like promising “a little kid a pony in barn, and then you get them a little playhouse with a pony in a barn.”

So while the agency behind this campaign is patting itself on the back for all the “buzz” created by these billboards, they should know it’s easy to create hype, you just don’t want to over-promise and under-deliver.

We call it the “punch and pie” rule. Don’t lure people to your meeting with the promise of punch and pie, if you’re not going to serve punch and pie:

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