Hendy commented that Ning isn't open source.

Agreed. I'd like to see an Open Source online web-app development / code-generation / code-management / code-sharing platform. Possibly Trac could evolve in this direction (from a very different starting point.)

I notice that I missed something from the list of improvents (in that previous post I linked) in web development. I said templating-oriented development (eg. PHP), and object publishing systems (eg. Zope) were the only real changes from trying to program web-apps as though they were any other kind of app.

Perhaps I need to add continuations based servers like Seaside. I finally watched these videos and got how cool this is.

Essentially you're allowing the language to hide all the session / interaction management.

Who owns the on-demand customer?

Joel trolling the Ruby community (yes you are, you know it)

Meanwhile, wouldn't the practical thing to do be to write the little bits that need to be fast in C?

The moral of the story is simple. You should see Heavy and YouTube as opposites in strategic error. Heavy doesn't create enough value consistently enough to be able to exert enough pressure to capture a significant share. YouTube, on the other hand, is creating a great deal of value - but also can't exert enough pressure to capture a significant share.

Bubblegeneration Strategy Lab

Trac Hacks is the free-for-all wiki-market where you can find Trac plug-ins and extension macros.

What's one of the most amazing, cool, web-based apps that no-one talks about?

Trac.

It's not flashy, or Ajaxy. But this packs so much useful functionality. Every time I show this to a developer, they drool.

Right now, if I was building a wiki-like application product for use in enterprises, or something to compete with Basecamp, I'd seriously consider starting here rather than with the usual Rails or Turbogears etc. It feels so well thought out that I bet the code is nice. And it's extensible.