Seeing that with the "new rules" certain sub communities could theoretically splinter off SO, like say a Python or a PHP community, will this be allowed and supported?
I have seen some (small) splinters; there is an iPhone SE for example. Personally, I hugely value the cross-fertilisation of ideas on Stack Overflow, so I really don't want that to happen.
That is also one of the things I find so objectionable about the iPhone SDK, btw. Seriously? The actual released API is under NDA? Get behind me, Apple! (throws salt, etc.).
I think the SE rules are more for your "fly fishing" site. So I don't see this as a threat to Stack Overflow. Jeff wants the site to thrive, too ;-p
If that is the case then every single programming could have a separate site. Existing SO helps me to learn A-Z in what ever language. "Get into SO, you will get answer for all the question regardless of languages". I say this statement to all my colleagues. I feel that the uniqueness of SO will lost.
I'm not sure such a thing will be allowed by our Dear Leader. Stack Overflow is the crown jewel in the Stack Overflow LLC crown; if we start to splinter the site it's going to turn into a mess and could be a really bad thing for us as a community as well.
I'm not exactly sure where things are going with this whole Stack Exchange 2.0, but one thing I wouldn't want to see is having the community torn apart by it.