A hell of a lot, albeit indirectly. Let me give you a hypothetical example: an engineer in a remote community in Indonesia needs to consider a water purification plant, not something he had previous direct experience with. Do this please: Google "water purification" and go to the Wikipedia article - pretty good, isn't it?

It is as useful in health, environment, economics, education and a whole lot of other fields. Have I convinced you?

Wikipedia is the first places I go when I'm trying to learn something new. If not for the article itself, the reference links at the bottom are a great place to start.

Not really, to be honest. I know this argument, but do you have evidence? I'd like it to be true, anyway.

A lot of the text in that article isn't particularly actionable. The cheaper and simpler purification solutions could use more detailed information on how to construct them and where to look for available tools, materials, or devices (e.g. organizations which help distribute them, or existing things which can be repurposed). That's not really the point of Wikipedia though, especially since this some of this information needs to cater specially to each geographical area.

As for the engineer who's looking to build a water purification plant, surely the information on Wikipedia is not detailed enough to help significantly and would pale in comparison to the other resources available to someone with the means to build a plant in the first place.

Evidence... how about this: http://xkcd.com/903/ ?

"Water purification" was this first thing that popped into my head based on your "basic necessities" comment earlier. The article is in fact an extremely good starting point for a competent engineer with no special knowledge of the matter. It describes the issue and outlines solutions, with linked references to further research if needed. And yes, it is detailed enough to help very significantly. I tell you this as a practising engineer with little knowledge of water purification myself. I am surprised you think otherwise.

Care to respond rather than downvote several of my posts without comment?

I did not downvote you, I was away from the computer for the last few hours. However your comment is so disingenuous that I am wondering if you are trolling. To wit:

- "A lot of the text in that article isn't particularly actionable" - what does this even mean? Does all of the text have to be actionable, let alone particularly so, for it to be useful?

- "...simpler purification solutions could use more detailed information on how to construct them" - no, this would not be appropriate, Wikipedia is not (yet) a detailed manual on how to do absolutely anything. But I think you implicitly admit that a good starting point has been provided.

- "...the information on Wikipedia is not detailed enough to help significantly" - yes, it is, it gives you the background, explains the jargon and provides hyperlinked references into whatever area you might need more information on. Not quite sure what your definition of "help significantly" could be here.

I will not be online for a couple of days, so if I have not convinced you, let's agree to disagree.

Cell phones are currently revolutionizing life for the better in unexpected ways in many of the poorer areas of the world that only recently got cell phone service as their first phone service of any kind. Marc Andreessen and Ben Horowitz have made a good argument that smartphones will soon be cheaper than conventional cell phones, which will be all the more true in nations where few if any patents have ever issued on all their special sauce. In the next decade, untold millions of the world's poor will be acquiring smartphones as their first and for a while only computers, and gaining access to all the benefit of the Internet.

Wikipedia is a good thing, it is better off we try not to compare it with other "good" things.

We're discussing merits of donating money, so I think it's worthwhile to compare.