Disclosure: I created Just Landed. Thanks for posting the app on HN!@frisco: I can understand how you lumped Just Landed in with other Silicon Valley startups some of whom are creating frivolous apps and raising vast sums of money against small ideas. I suppose those irritate me too for the same reasons you mentioned.
However, in this case, you would be wrong to assume that Just Landed is just another overfunded startup trying to conquer the world with an airport pickup app. First off, Just Landed is not a startup. Just Landed is an app, built by myself and two of my buddies, because I kept making the mistake of forgetting to leave for the airport on time to pickup my girlfriend. After finding that no other apps were solving this problem (and that flight apps generally sucked), I decided to take a crack at it.
I don't make any claim that this is an important problem in our society (I built this app for myself), that this would be a good idea for a startup (it probably isn't), or that it's worthy of venture funding (so far it's not a great business). Just Landed was built with $15k of my own money as a fun side project while I figured out what I wanted to do next with my career. Frankly, I'm amazed how successful it has been - it was totally unexpected. Also, it's not even really a company - it was released under Little Details LLC because I needed to protect myself with limited liability (I also plan to make other commercial apps).
Finally, while we have certainly had offers, it is also not my goal to be "acquihired". I'm actually working on a mobile game right now, and am thoroughly enjoying myself. My goal is to be free to work on my own fun projects for as long as I'm able. If I come upon an idea worthy of a startup, something that can really change the world, that's a different story. FWIW I've already failed twice at a startup (went through YC once), so for now I'm taking a break and building apps.
Just Landed is not going to change the world, but it sure saves my ass (and helps hundreds of thousands of other people) when it comes to going to the airport to pick someone up.