Medium that reveals flaws
A medium that reveals flaws is a medium that reveals the flaws of the content produced in it.
- A table makes it obvious when one of its cells is missing information. Once you specify the column names and instances (rows), that automatically gives a spot for n*m cells which must be filled. If the same information is presented as an essay or news reporting, it is not so obvious which pieces of info are missing.
- Jonathan Blow makes the point that a video game designer must create a system with consistent laws/mechanics, whereas a novelist does not need to do so.
- "Do the math, then burn the math and go with your gut": writing down actual calculations and probabilities and so forth enforces consistency and a crisp model in a way that just using verbal reasoning + intuition doesn't. (Paul Graham's advice to do things that don't scale might be similar.)
- "Plans are worthless, but planning is everything"
- Redlinks on a MediaWiki wiki makes the divergence between intent and execution obvious, in a way that "just don't link to it if the page doesn't exist" (the default on the web) doesn't.
- Empty sections similarly make intent vs execution obvious.
- Designed interfaces: "But the new representations you develop may be held entirely in your mind, and so are not constrained by traditional static media forms. Or even if based on static media, they may break social norms about what is an “acceptable” argument. Whatever the reason, they may be difficult to communicate using traditional media. And so they remain private, or are only discussed informally with expert colleagues." 
- Writing/language in general has a little bit of this flavor (see, e.g. Writing forces sharper understanding, and "Converting thoughts to speech slows down the thinking, but increases the discipline and may dramatically enhance creative outcomes"), but in my view it is not sufficiently exacting. Jonathan Blow likes to talk about how fiction writers can write any bullshit they want.
- deluks's post about how step-by-step instructions are easier to critique and find flaws in is another example of a medium that reveals flaws [this was in the context of bitcoin]
- "future work" section
- "citation needed" on Wikipedia
I think one difference between me and most people is that I am much more likely to choose media that reveal flaws, to expose the limits of my knowledge.
How do we classify something as an example or non-example? some things to pay attention to: whether the thing is structural/a medium, rather than just a particular way to use an existing medium? whether there are other (e.g. social signaling) explanations for the behavior
To some extent, whether a medium reveals flaws is a matter of degree. For example, speech allows people to mumble their way through the parts they are uncertain about, which written text does not allow. So relatively speaking, even prose is a medium that reveals flaws, just not as much compared to something like a table.