Agree completely about Scratch. We have a love/hate relationship with it--it gets about 80% right but it isn't pretty and onboarding is a struggle. Scratch 2.0 will be coming soon with some improvements but still in Flash (!!)
The great thing about visual programming languages is that kids can focus more on the concepts and less on bugs due to syntax/typo errors. We're working on one for the iPad called Hopscotch - gethopscotch.com.
Well, I think some kids care about the abstract and fundamental workings of computers, but a lot are initially interested in learning programming because they see cool stuff and want to make it themselves. Teaching them the "just in time" simple concepts that lead to concrete results without making them struggle with syntax to start out is a good way to keep them motivated initially. Then after you hook them, you can start teaching them the fundamental concepts of how stuff works.
I think you'll find plenty of upwardly mobile and reasonably successful adults on HN that know how to program. Many of the best started as little kids. And as software increasingly touches every aspect of our lives, knowing the basics of programming will be useful for understanding how things work in the world.
Brain surgery is a highly specialized discipline that takes years of preparation before the surgeon makes her first cut--Daisy the Dino is specifically trying to make programming less intimidating to learn with a lower barrier to early success.
There's a fundamental difference between building a product that doesn't depend on others for its functioning, and a marketplace, where the core function is access to other users.
It is about impossible to get a marketplace going from a standing start. I've commented on it before elsewhere: picking off Craigslist users was always critical for Airbnb to get going. There are dozens of startups trying to build companies off the back of what Craigslist doesn't provide.
I'm sure the Airbnb guys probably started with the honest approach, realized it got them nothing but cease and desist notes, so switched to the craftier fake emails from girls interested in the well-being of vacation renters everywhere. I bet it felt icky at the time, but here they are. And "you know what's cool....?"
I see that too. I keep hearing time and again from investors like Fred Wilson and Chris Dixon that amid the difficulty of attracting and retaining good talent, the "unicorn" is the killer product person.
Completely...I've been in the same position for a while. There are dozens of apps, hacks and sites (some competitive with yours and mine!) launched every day by creators that have identified and are trying to solve legit problems --the same ones you're trying to solve. Thing is, most of these creators don't have 1) the design discipline to make the products really appealing to serve their niche consumers and 2) the forbearance to stick it out during the inevitable long iterative process. Which means that if you have confidence in your own ability to do those things better than a competitor (especially if what you're doing is "not exactly" what the it does) then, onward!