I happen to think that Google, FB & such were founded with a solid ethic. I think Google meant "don't be evil" when they said it. But, the questions come later. Will you increase consumer privacy at the expense of CPCs (and value to advertisers). Will you de-fund some of your blue sky R&D to balance reduced yield on advertising.

Wikipedia is the right model. After all this time, they really are still focused on wikipedia's original goal. I am personally very happy that Wikipedia exists.

The way Wikipedia is supposed to scale, is not by making an amazon-scale wikipedia. It's by doing their job well, and being a prototype/inspiration for others to do other jobs. If Wikipedia was a social network, maybe it would not have "scaled" to also be the world's no. 1 news source. Maybe it would not have become a major IM app. That's not a bad thing. We didn't need Facebook to take over news. We could have gotten our news elsewhere. We didn't need facebook to do IM, same reason.

Wikipedia is not a failure because it didn't scale this way, it is a success for that reason. Being not for profit has let them pass on opportunities for land grabs, in a way that for profits would not have resisted.