Because you get answers from experts. And lots of answers, so you can compare them. It is more like asking a friend for the answer - and having a circle of friends who include e.g. airline pilots for questions about airplanes, astronauts and flight engineers for questons about astronauts etc etc.
Unless you have a very wide circle of friends, chances are you find answers here, that you can't find by asking them.
If you search online, then what you find is selected according to your biases. Some things may be easier for you to read, or fit your preconceptions, but false. Lots of urban myths are propogated on the internet, that sound convincing (that's how they are propogated) but are completley untrue.
You might think that wikipedia would fulfill this role. But there are problems with it.
- It is often far too technical for most people. The articles have to be written in a rather dry "encyclopedic style" - you'd never get amusing and interesting sidelights on the question in forms of videos, images etc, or personal anecdotes. And the more advanced mathematical articles for instance are primarily written for mathematicians, very hard to read if you haven't got a degree in maths. Same for many other topics, you have to be reasonably advanced to follow wikipedia, even though they do their best to make it accessible to anyone.
- It is quite often inaccurate. Not always by any means, many articles are excellent. But a few are inaccurate. For instance, I've been trying for several years to get them to change a statement that says the surface of present day Mars is uninhabitable for microbes. This was the prevalent scientific view up to about 2008. But everything has changed in the last seven years. The editors are not expert in their topic area, quite often. Sometimes they may be somewhat stuck in modes of thought that are five to ten years out of date.
- It often doesn't report leading edge research unless it hits the news in a big way. If it is going on in a quiet way in the scientific journals, and never hits news stories, may well not get into wikipedia. That's because it requires you to read a technical paper and summarize it for wikipedia, which is frowned on in some topic areas.
You have to wait for someone else to do that first, in a review paper or some such. Which probably won't happen for a year or two, maybe longer if it is somewhat specialized, making wikipedia often a few years slightly out of date. That's especially so if the research overturns previous prevailing views in the field.
This depends on the topic area a bit - this is their rule on primary, secondary and tertiary sources.
It just says secondary sources are preferred in the guidelines, but I have found that though in many areas they do permit you to summarize technical papers in the articles, in a few topic areas, editors enforce this rule very strictly, more or less prohibiting any use of scholarly articles as sources unless backed up by a secondary source. - It doesn't do personal anecdotes, things like sharing what it feels like to do things.
- It will only include images if they are marked as suitable for re-use, with modification, for commercial use. There are many excellent images that you can use to illustrate articles, that can't be used in wikipedia. It also doesn't let you embed youtube videos.
And outside of wikipedia, unless you know where to look, it is often hard to tell what is accurate, and what is just made up or half remembered information, not well understood "facts" or indeed sometimes out and out spoofs, not meant to be taken seriously.
On quora, there are enough experts in many topic areas so that answers like that probably get comments by others pointing out the issues in them.
You should be aware though that quora contributors can switch off commenting, so no comments doesn't always mean that everyone else agrees with the answer. But in that situation they are often corrected in other answers anyway.
It works so well because it has managed to attract many experts to contribute, somehow.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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