this is something we absolutely need to do. Here's what i know:

1) we will make a basic approach page that outlines preferred labels and approaches to common UI problems.

2) I encourage you all to send us feedback/questions as you work. You can always send someone a private message through their profile, so if you want to get some feedback on your solution to a new problem by all means reach out to me or andrew.

3) we will be reasonably open about adding your stuff, but reasonably frank about our perspective on it. Much as c5network members now have badges that help you understand the weight of their advice, we're going to be adding attributes, badges, and awards to everything in the marketplace. We hope to make iteasy for a casual visitor to search for stuff that will all have a similar feel and expertise requirement to use. We'll be somewhere between the AppStore for iPhone (ruled with an iron fist) and the Drupal add-ons (anarachy).

4) we will be asking ourselves a set of consistent questions as we review your submissions:
a) does it work as expected?
b) is it easy to understand for a casual (untrained) human?
c) does it break anything else in the marketplace?
d) does it feel "c5-ish"
e) is it good for the marketplace? (license concerns, duplication concerns, etc)

based on how we feel about all of that together, you'll end up with a page you control in the marketplace. The forums, bugs, feature requests sections are all yours to run. There's a path to update the file that a purchaser/picker gets so you can deal with updates. Once someone has bought the app once, they have access to download it and its updates again - although we encourage a per c5 instance license model. (more on that in coming weeks)

Frankly our goal is to fill the marketplace and empty the core. If there were an easy way to pull a few blocks out of our core distribution today, I'd do it. There should be simple hooks to install themes, blocks, and packages - and the core should be a fixed goal.