As everyone has said the announcement contains no technology news.

The early adopters who are accepted into the program get dev kits so assume that's the same C++ SDK that consoles already have.

Unity have announced they will support it - but no date/price. Typically console unity licenses are not cheap.

There's no sign of any XNA like team so all bets are off there unless its super secret.

There's plenty of rumor of Xbox One supporting HTML5/JS but that would be a strange limit for indie games

And finally we know there's a windows instance on there so its not beyond the realms of imagination that is a target too in which case Windows8/WP8 would seem like something to look at.

The Mono.Game guys would love to support Xbox one so if Microsoft goes the Windows 8 route then I am sure they would support that. I know they have tried to apply in the XboxOne Indie sign up and I'll be letting some folk at Microsoft know that its a good idea. There's clearly a ton of managed code desire from the community since this is now the #1 .Net request http://visualstudio.uservoice.com/forums/121579-visual-studio/suggestions/4233646-allow-net-games-on-xbox-one

Seems like initially its going to be a select group of indies let in - probably already proven people. The masses get let in later - again date unknown. But really Microsoft need to let people know what to start work on. If we all need to move to Unity so be it but let us know.

[Speculation] Microsoft Kodu will probably have some kind of non-programmer-friendly iteration on the new Xbox. For us programmer-types, we'll probably have a new from-the-ground-up XNA-type API. I bet Windows 8 apps and Windows Phone 8 apps will also have some kind of semi-easy migration path for porting to the XBox One. [/Speculation]

Kodu is so Xbox 360 - Xbox One is all about Spark https://joinprojectspark.com/

What about the PS4, do we know anything there?

They are being pretty generous with dev kits to proven indies apparently but once you have the dev kit you are stuck behind an NDA

There's no news technology wise from them either but of course it supports C++ and Unity will be working there at some point if you have the $$$ too.

There's several mono.game based games been mentioned - but nobody has confirmed if the PS4 versions will be ports to C++ or if Mono.Game is running on PS4 - I am sure they too would be NDAd

As Dave said, they havent announced anything.

My personal bet is there will be nothing like XNA for a few years to come, we wont be able to develop for it in the same way XNA was a download and go kinda tool, they will make you pay for a dev kit and the SDK.

These are my opinions, not fact

There are a lot of things like XNA that people aren't even aware of.