write insideThe categories of technology on display at SXSW range from frivolous social media apps and frivolous marketing gimmicks to totally mind blowing innovation-for-the-sake-of-it technologies, and the utilitarian “we’re making your life easier” services.

I placed my bet that this year SXSW would deliver a big boost to Sidecar and Uber. The companies offered their peer-to-peer taxi services to the public for free, solving a massive getting-around issue for party hoppers and those staying at far-out hotels. They shouted about it from the rooftop. Sidecar’s founder told the Verge he was hoping for a Twitter-like spike in adoption. And it did get buzz. I asked dozens of people what they thought was cool at SXSW this year; the vast majority mentioned Sidecar and Uber. Surely the stunt boosted downloads, often in a very frustrated moment of needing a car rightthissecond. And then, as Michael described earlier, those downloaders waited. And a car never came.

This situation — a free, hyped up thing that no one really has access to — is like the Girl Talk Party thrown by National Geographic. The company collected thousands RSVP’s for a several-hundred-person venue. The line was already five blocks long, hours before the event began. The vast majority of people in line had no chance of getting in. “Why didn’t they just cut off the RSVPs at a certain point?” someone asked. The answer is obvious: Look how cool it is to throw the party with the hardest door in town. Not to mention, now NatGeo has all thousands of email addresses, instead of just hundreds.

It’s the same thing for Uber and Sidecar. We all downloaded it in that desperate “I need a ride now” moment. And the few of us who actually got rides were sure to Tweet or Vine about it. (Is Vine a verb yet? I’ve just decided it is.)

So yes, Uber and Sidecar won downloads, frustrating everyone in the process. It’s one thing get annoyed when Twitter crashes. Oh no, I cannot access a fast-moving stream of mostly frivolous information. The inconvenience level is “barely.” It’s another when we’re failed by a service promising to solve a logistical problem.

That’s why the actual winner of my SXSW was ZocDoc, even though the company (as far as I’m aware) had no real presence at the festival.

Somewhere in the middle of the festival I managed to crack a molar tooth crown loose and swallow it (thanks, brisket). Monday morning, I searched for Austin dentists within a reasonable walking distance. Apparently I wasn’t the only SXSW-er with dental issues — I got no answer or a busy signal for most of them. I walked to a few nearby offices — no available appointments. Getting desperate, I downloaded ZocDoc and within five minutes, had secured an appointment with a well-reviewed dentist, filled out paperwork, and confirmed it.

Before today, I’ve never thought the problem ZocDoc solved was that massive, because I’ve used the same doctors for years and had no trouble finding them and getting appointments. I thought that if I don’t need new doctors, I didn’t need ZocDoc. Sure, the company is helping lots of people find doctors, but did it really need $95 million in venture backing to do so? Did it really need 300 employees for a slightly better alternative to Google?

The answer (“YES”) is much clearer to me now. ZocDoc turned a moment of desperation into a seamless fix. The process was so simple that I plan to book all appointments through it. I’d even consider switching doctors in some cases if they don’t use ZocDoc. And ZocDoc Check-in, introduced last year, made it so that I did not fill out a single form when I arrived at the office.

If this is all old news to you and you were waiting for me to reveal a smarter, more brilliant insight, I’m sorry you got this far. The takeaway is this: If you’re setting out to solve a real world problem, and you’re going to advertise it as a genius solution, you better deliver. ZocDoc did. Uber and Sidecar didn’t.