Short Version: My impression of the selected questions & their associated answers is generally positive. I'm not thrilled with all of them, but I don't think any are terribad.
OH GOD SO MUCH TEXT MAKE IT STOP version:
Subjective Overview
The only thing "wrong" with this question is that it doesn't specify what country's regulations they're asking about or what their flying goals are (Private, Commercial, or Military), which makes it difficult to answer definitively. (Unfortunately these are things the asker needs to fix - there's no obvious way to fill in the blanks from their question & profile.)
If the asker returns to fix the deficiencies noted this is a "good question" - it's one a pilot or someone directly involved with aviation probably wouldn't ask, but someone interested in starting a career as a pilot would certainly want to know if they're age-limited (particularly if they're considering a career change later in life).
"Helpfulness"
There's not enough data for a statistically meaningful assessment of how "helpful" this question is, and the question itself isn't detailed enough to evaluate the answers for "correctness".
The answers that were posted before the question was closed do attempt to give some insight that might help point the asker or subsequent visitors in the right direction for their own research (this one in particular stands out).
Overall I would say the answers here "make the internet a better place", though they're not as solid as I think most of us would like to see.
Versus other sites
This question is asked constantly on forum sites. The answer almost universally points to the FAA regulations (because those sites tend to be USA-focused).
We do not link directly to the FAA regs, but that's because the community made a conscious decision NOT to limit the site scope to the USA and instead to try to determine what regulations apply in the poster's specific situation.
Subjective Overview
This is the sort of question we'd expect from an advanced private pilot or an instrument student - about the only thing missing from the question is a link to the "report" which would give people looking to answer it a starting point for their research and explanations.
"Helpfulness"
There are enough views and votes here that I think the feedback on the question and accepted answer can be deemed "overwhelmingly positive". There aren't enough anonymous votes to definitively say whether the internet at large agrees with the community, but as there are no downvotes from either group there seems to be a consensus of opinions.
The answer itself uses the broad wording of the question to lead into a good discussion of the subject at hand (the various types of ice, when they form, and where they tend to appear). It also links to a number of respected and credible sources for additional reference and research, so folks wanting a more in-depth explanation have somewhere to continue looking. About the only thing it doesn't cover is "Does ice accumulate on the inboard part of the wing first, or the outboard part?" (which is something the sources also don't address - I imagine there are a number of factors that would contribute to that answer on any particular airframe, so they concentrate more on front/back position of the ice accumulation & its affects on de-icing systems).
Overall I would say this question & answer makes the internet a better place.
Versus other sites
The answer here is a consolidation of information available from other resources (which are linked to). While we're not creating "new knowledge" with this answer we are presenting it in a quick, condensed form & providing links to source sites.
There's value in the condensed form of the answer that we're presenting, and providing the "expanded" answer via external resources seems to be the best way to handle discussions about icing: A full discussion would quickly become too dense for many readers.
Subjective Overview
It is not surprising that this is the most-viewed question in the sample set: Anything about military aviation, commercial aviation, or timely questions about aviation accidents tend to accumulate views quickly, and maintain a high level of interest. They're also Google Candy: This question is the second result when I ask Google Why are aircraft carrier decks angled to the left?
Because of this popularity this question has wound up "Protected".
This is rapidly becoming our standard practice for such questions.
The question itself is clear and well-scoped.
"Helpfulness"
The overall impression from both the community and the anonymous users who have voted on this question is positive, and there's a good correlation between the two.
Sadly we don't have many (any?) naval aviators or aircraft carrier designers around to give definitive answers on this subject. The top 3 answers give sound, plausible reasons though, and they cite at least one compelling source.
If I were to find fault with this question & the answers it would be that "the answer" requires reading at least 2 posted answers to get all the details. This is a common problem with questions where we don't have a de facto subject matter expert on the site to give a detailed write-up.
Overall I would say the answers here "make the internet a better place", but I wouldn't hold them up as an example of our best work.
Versus other sites
The other site I would compare us to here is Quora - the #1 response in my Google search.
- The Quora answer is better organized than ours, but also only concentrates on one aspect (flight safety & aborted landings).
- Our answers include references which provide the history of the Royal Navy's rationale behind angling the deck to the left as opposed to the right, which isn't covered in the Quora answer or comments.
I would say it's pretty much a wash.
Subjective Overview
Another military question, and another highly-viewed one.
This is one of those questions where the answer is sort-of self evident if you're a pilot or have an understanding of how lift is produced by a wing, but it's a good general-audiences question.
"Helpfulness"
The accepted answer gives the "Why", but is perhaps a bit too technically dense for a novice (how many people off the street know what "wing loading" is?) - it at least puts the answer within easy reach though.
The other answers and comments…sort of muddy the waters more than they help. At least one seems to confuse Effect and Cause to some extent.
Overall I would say the existence of this post makes the internet a better place, but again I wouldn't say it's the site's best work.
Versus other sites
There don't seem to be any directly comparable questions elsewhere on the internet (at least from cursory Google searching: Our Q&A is the top result, followed by several irrelevant results).
Subjective Overview
This is another good "general audience" type of question - something many people have probably wondered sitting in the back of an airliner.
It could be argued that the question is more a physics one than an aviation one (really the only thing contrails have to do with aviation is "you see them behind jets"), but I would consider it appropriate for the site.
"Helpfulness"
The top two answers provide the "How" and the "Why" behind the formation of contrails, and explain why they are (usually) not visible from the cabin. they also provide an example of at least one case where the contrails were probably visible from the cabin (exterior photo, so we can't be certain).
The third answers is "more a comment than an answer" and is a good example of the most fundamental misunderstanding of "This is a Q&A site" that we see, but it's not bad enough where I would delete the answer: There is some value in the examples it provides.
**Overall this question and its answers "make the internet a better place", while there are lots of web pages about contrails the explanation here is distinct from what I've seen on other sites and covers a slightly different aspect of the subject matter.
Versus other sites.
I refuse to search for contrail-related things on the internet on the grounds that I will wind up reading some chemtrail conspiracy theory and throwing my coffee mug through my office window. - Sorry, you're on your own with this one :)
newid()is sketchy: It picked what I'd consider a good representative sample in your original query, but when I cranked the anonymous feedback parameter the sample set wasn't anywhere near as diverse. $\endgroup$