Also, in my opinion, it won't be possible/wise to explain what's explained in the video by typing it out the same on MSE as:

1. Video is around 20 mins long and introduces and explains a lot of new concepts.
2. Typing out the final result will be of no interest to the OP, or to someone who checks that post later, as some explanation/background is required/needed.
3. In case of some other video which even if doesn't explain/introduces new topics/concepts, but has a very long solution which rather be not typed (again).

Note: One argument may come that simply mark such a question as under-researched, but that won't be right as the OP has already tried it and could not find the answer anywhere (thus, MSE) but the friend was able to find one because he had talent [:-)].

Example:

Q: Finding the number of integral solutions of the equation: $$x^2+y^2=265^2$$ using linear equations or the properties of the "primitive" Pythagorean triplets?

A: Hope this solves your problem.

• May I also know the reason for downvotes? Jun 27 at 19:10
• On meta, there is no reputation, hence votes tend to be used differently than on the main site. You should interpret downvotes to mean "I don't agree with you". In this case, a downvote probably means "I don't think that a link to a YouTube video is a good answer."
– Xander Henderson Mod
Jun 27 at 19:17
• @XanderHenderson thanks a lot for this brief but very useful explanation. Wasn't aware of this and was even shocked to see the downvotes, though I ediited my question for good anyways. Jun 27 at 19:20
• Your example question can be solved easily in a few lines without a video. If a video solving that problem can't be summarized in a few lines then it probably isn't worth watching. Jun 28 at 3:08
• Here is a bit similar question from 2013: Is it allowed to answer a question with a (YouTube) video? (The site might have changed quite a bit since then - but looking at the responses at that posts and here, they seem to be in a similar spirit.) Jun 28 at 5:02
• @MartinSleziak thank you, while posting this question, I viewed the link that you have shared but since the question wasn't exactly what I wanted to ask so I posted my question, but now that I read the answers they really seem to address my question too. Jun 28 at 11:21
• So, inan, you were aware when you posted here that there was an earlier related post, but you chose not to mention this? Bad choice. Jun 28 at 23:26
• @GerryMyerson I didn't know I should, I generally mention related posts in my question but sometimes when I think it's required I don't. Didn't know I always should. Anyways.... noted. Thanks. Jun 29 at 3:40

Link-only answers are not (ever?) appropriate since they typically lack context, and often there is no assurance the target will remain available. In short, they are not self-contained or reliable enough to be a good solution.

That said, it's not a bad idea to provide it as extra information after a substantial answer, or as a comment.

At the very least, one could summarize exactly what's done in the video that solves the posed question, noting, if necessary, that the complete justification is too involved to write out. This might be enough to give the solution enough context to survive scrutiny.

• It is possible that a link-only answer might be okay for a reference-request question. I am (generally speaking) opposed to the idea of link only answers in any context, but community consensus, I think, is a little more forgiving when the asker is looking for a reference.
– Xander Henderson Mod
Jun 27 at 19:11
• @XanderHenderson Yes, good point, that's one potential exception. Jun 27 at 19:11
• @rschwieb assurance with respect to availability is a problem sort of ubiquitous on internet and so true with MSE too. Secondly, the context part I don't get. If someone answers just via YT link, they would have ensured the context is present there. Lastly, could you check the example I have just added in my post. Would love to know your opinion on it. Jun 27 at 19:25
• @InanimateBeing It is not at all problem if you write a solution that is a solution. The solution is either there or not there, and it can never become a null pointer. You may check to see if a youtube link is there when you link it, and three days later the poster may decide to delete the video. This is why links are only partially reliable. Jun 27 at 19:27
• The underlying issue, @InanimateBeing, is that sites on SE attempt to be complete, encyclopedic, and self-contained. If your answer comes down to "Read this book," or "Watch this video," then you haven't answered the question; someone else has, and you are just pointing a user in the right direction. This is fine as a comment, but is not appropriate as an answer.
– Xander Henderson Mod
Jun 27 at 19:29
• Ohh, ya, the COMMENTS! Yup that seems fair enough to me. Thanks a lot again @XanderHenderson. You saved me from an endless argument with rschwieb :-). Jun 27 at 19:33
• I'm not sure why you would agree with me and not @rschwieb (since I agree entirely with everything that they have written), but I am glad that I could help.
– Xander Henderson Mod
Jun 27 at 19:40
• @XanderHenderson true. Just read the answer again and seems I over looked that the answer post too suggests comments. Now accepted as answer. Aug 3 at 11:02