Apple: 200,000 iPhone developers so far
macworld.com
macworld.com
I bet only 10% of them will ever actually ship anything (10,000). Of these, probably 90% will suck (1,000).
It still seems like enough to have quite a few really awesome applications that cater to enough lifestyle/professional niches (photography, GTD, CRM, ...) to create a little bonzai-tree software ecosystem, one that Apple has by the balls at all times.
On the whole though, I'm expecting Apple to really push this, as they're talking up the App Store as a whole new market for them to enter into. They're not about to take the risk of harming their developer base.
i'm as big an apple fanboy as anybody, but this is making me suspicious. i'm in wait-and-see mode.