I've started a draft of the requirements for the first release of Flow to a real live Wikimedia project: http://www.mediawiki.org/wiki/Flow_Portal/MVP. This is still just a draft and very much open to more input, so please have a look and let me know what you think, either here or on the talk page: http://www.mediawiki.org/w/index.php?title=Talk:Flow_Portal/MVP.

As I think some of you know, we've shifted the focus of our first release from user talk to WikiProject talk (yay, pivoting!) to give us some time to figure out how to deal with bots, tools, and user warning/messaging/blocking workflows. Instead of trying to solve all those hairy problems in our first release, I want to be sure we can first and foremost handle the core peer-to-peer discussion/content collaboration that talk pages are meant for, and I think a WikiProject talk page is a good test-bed for making sure we've got those pieces nailed down. The plan is to: 

1) Build a fully functional prototype on Labs based on the above requirements, in order to let the community come kick the tires.

2) Specifically invite facilitators and members of some active WikiProjects (on enwiki, but not necessarily enwiki only) to give the Labs prototype a try and see if they'd be willing to trial a beta version on their WikiProject discussion space for some period of time.

3) Release to a few WikiProjects that are game, gather data, bugs, feature requests, and keeping working to make Flow the most kick-ass wiki discussion/collaboration software of all time :) 

4) When we're comfortable that we've satisfied the requirements for WikiProject talk, we'll begin working on the next set of requirements for other discussion spaces (probably user talk).