Lots to talk about here...
Absolutely. All reputation is contextual. What we're poking at here is what are the reasonable common contexts for forums.
Please, interject more @smarsh2008!
If we need to go all graphy, we should. But I agree, I'm not at all convinced that we've identified a need for that just yet. Let's tease apart some cross-forum or cross-category reputations first.
But @ChrisHanel raised some detailed points (at my request) and we should look at each one.
Though I'm not sure I agree with the graph showing these two values as the X and Y axis, I think there is much good to mine from this basic definition.
There are at least two good wide-ranging karma scores we could calculate. I'll name them formally to expedite discussion:
AuthorContentQuality [ACQ] which derived from ItemContentQuality [ICQ] which derived from Evaluation Statements, such as Like, Favorite, Flag, Bookmark, Reply, etc.
AuthorEvaluationQuality [AEQ] which is derived from either/both of Moderator Verification Statements or Peer Agreement
In fact, these are very similar to the core scores in many social media content quality reputation systems I've helped design/build. You can read in great deal about one here: http://buildingreputation.com/doku.php?id=chapter_10
One could go further and suggest that there exists a function (f) where:
f (AuthorContentQuality, AuthorEvaluationQuality) = ContributorTrust (CT) <-This creates a 2d graph...
But I'm not sure that we should use the combo score (CT) to assign all features/rolls. If we have multiple contexts, why not break up the roles/features along those lines? If you have a high AEQ we consider giving you more moderator tools. If you have a high ACQ - more content creation/publication tools. What would be the purpose of assigning role-descriptive text-names to each (ACQ,AEQ) sector - it just leads to confusion: "Why can't Scholars do foo? Why can't Jr. Moderators do bar?"
And - what are the other contexts that are reasonable for the various uses of Discourse? There are certainly arguments to be made for per-category trust scores - especially if a forum has very differing "rules" per category (SomethingAwful and Penny Arcade come to mind.) It seems that someday having per-category permissions will make sense. [I'm not rushing to add those features just yet, just wanting to make sure that we don't design ourselves into a box.]
On to Chris' bullets - they all deserve responses:
Static levels don't have to scale linearly. Also, I've already mentioned decay elsewhere:
Also, putting in a latch to prevent a users capabilities from wavering back in forth is technically trivial. Note that this is an edge case that doesn't happen often, and the user should be informed whenever (s)he's demoted and what to do about it. In short, if you care it won't happen. If you don't care, well - it doesn't matter.
What about this instead? The cases are 1) Features are granted automatically (default), 2) Features are granted by Moderator fiat only. In both cases, the forum operator may opt-in to be notified whenever a user crosses a major threshold. That covers all the cases I can think of (preemptive, reactive, locked-down, and laissez-faire.)
Why have role-titles if they don't do anything or aren't clear? As to fine-grained feature grants on a per-user basis - I've seen up-close that tried at places like Answers.com. It was an administrative (and interface) nightmare - especially when you have administrator per-feature per-user override.
Again - confusion around titles - either they mean something (to everyone) or they don't. If I see you are a "Moderator" - believe me, I have some expectations that you will act, and quickly, when you see a goatse post - abdication of authority/responsibility is not an option. Not acting in that case should lower your AEQ significantly and cause you to lose the power/title. Not to mention the possible side-effects should some content dispute erupting in the real-life "legal" arena from inaction.
Thanks for doing so! I'm sure others have similar thoughts and I know I've had this conversation with other companies when they are setting up their reputation systems. Honestly, you are already quite a few steps ahead of many of them in thinking...