MailGapp is a small company that solves a small yet majorly annoying problem: coming away from your post office box empty-handed.

Working alongside partnering mail centers, the MailGapp app notifies you when your mail comes in. So instead of schlepping a few blocks or miles to check your post box, you can simply check your smartphone.

Sounds limited, but MailGapp Founder Daniel Kaneshiro identifies at least one demographic that would find some major use in it: Realtors, who use post boxes because they are often legally required to have mailing addresses outside of their home addresses.

Kaneshiro said he developed the idea for MailGapp when he saw lots of mail center customers check their mail each day only to find there wasn’t any there. “They were wasting a lot of time each day doing this,” he said.

But that experience goes beyond realtors. “Everybody’s gone through this,” Kaneshiro said.

So MailGapp has the vision and the target demographic — but what about growth opportunity? For that Kaneshiro is looking at working alongside mail markers to target people even if they don’t have a post box to check. “We’re looking to take the ‘junk’ out of ‘junk mail.'” he said.

Unfortunately, the startup’s pitch didn’t go over so well on the DEMO stage.

“They’re solving a problem I do’t have,” said Googler and longtime startup guru Don Dodge during his onstage review of the product. “I pay every bill online; I do all my banking online … I just don’t do mail.”

Cisco comms executive Sheila Jordan concurred, saying she’d give MailGapp some credit “if they can eliminate junk mail. … Other than that, [physical mail] is already not part of our lives.”

Andreessen Horowitz partner Frank Chen summed up many investors’ point of view, saying that VCs tend to favor companies tackling problems that will exist in the long-term future. “This felt like a short [term] future kind of company,” he concluded.

MailGapp is one of 75 companies chosen by VentureBeat to launch at the DEMO Fall 2012 event taking place this week in Silicon Valley. After we make our selections, the chosen companies pay a fee to present. Our coverage of them remains objective.