Given a choice between giving a man a fish and teaching him to fish, you always want to teach them to fish. But sometimes that involves showing him how to put the worm on the hook first.
In cases like the one cited above, if there is any information or knowledge about the education and experience level of the person asking the question you can make a guess at their capabilities and the level of instruction they need. Based on that, you can determine how much information to just outright provide, vs showing them how to determine the answer, vs. just giving them to the tools to do it themselves. Then adjust as appropriate based on the need and urgency (ie. adjust towards just giving them the info if the question is "my house is on fire, and I need to know how to use a fire extinguisher RIGHT NOW!," and adjust the other way if the question is "I was too lazy to read the manual myself, so can you explain the entire game to me?").
But a lot of times, you can combine providing the answer with an introduction to the tools. For example, in
this thread, the direct answer was not provided in the reponse, but Ashley was directed straight to a web page that gave the answer. That provided a quick response, but also served as an introduction to navigating through the FIRST web site, where a lot of other answers are located.
The particular question cited by JVN is an interesting one. The initial question about the drive shaft diameter could source from anyone, with any level of experience, just in search of a quick answer. But then I would have all sorts of alarm bells going off as soon as I saw the response from the team "engineer" asking how to convert from millimeters to inches [please insert your own old NASA metric/English conversion joke here]. If they are going to have this role on their team, but they don't even know how to do this type of conversion, then this is a person in serious need of fishing education - fast! Point them to a units conversion web site, and let them learn to do it on their own.
-dave