Okay this is slightly tangential... but I think related to the quoted exchange... But can't you fail by succeeding in 4e? I mean there's a skill challenge example where you can succeed at your intimidation roll against the king (or baron or duke or something) and it impacts the challenge negatively... or am I missing something (honestly asking since I'm not sure I'm following the exchange and you are one of the posters I tend to take at face value when it comes to discussion).
I guess it depends on how you're running 4E! I'll propose three ways: 1. 4E "by the book"; 2. My game of 4E; and 3. A general "Indie" style.
1. In regular 4E (which confuses me!) I think that you can fail by using your Intimidation skill in the incorrect circumstances. I'm not sure if you'd forgo the roll - your PC misspoke, so you just rack up the failure - or if you'd still roll but count the result as a failure either way. I think you could succeed with your intimidation - the NPC may be intimidated, but it wouldn't get you what you wanted - closer to success on the skill challenge.
2. When I run 4E (or more correctly, my hack of 4E) I tend to run it like I run my 3E game. A little background on my techniques: I only call for a roll when what the player had his or her PC say triggered an internal conflict within the NPC. I recognize this internal conflict when I, as DM, don't instantly know how the NPC would respond.
I think we'd also have to define what success and failure means here. There are two variables: is the NPC intimidated, and thus I as DM have to play the NPC as being intimidated (in order to maintain consistency of the game world); and do you get what you want (not just an intimidated NPC, but a specific concession from the NPC)?
In my game I don't concern myself much with the latter - we roll to resolve actions, not intent. (This is one of the reasons I don't consider these games to be "Indie": I'm more concerned with player skill.) The NPC may be intimidated but respond by flight; but you wanted them to hand over some gold (or whatever your demands were). In that way, you could fail by succeeding.
The only time that wouldn't be true is if that last success overcame the NPC's obstinacy - the final success in the social skill challenge - or, in 3E, if the Intimidate roll adjusted the NPC's attitude to Friendly or Helpful (I guess, maybe not all the time).
3. I don't run "Indie" 4E, but I do run other "Indie" games. In Burning Empires, you are explicitly rolling to resolve the PC's explicit intent (as stated by the player). In this case, you get your intent when you succeed at the test. (Whether or not that intent helps you in the future is another matter.) I'd imagine that 4E would be run in a similar style.
So to sum up: 1. Yes. 2. Almost all of the time. 3. No.