The issue here is separate, for-profit redistribution in other media, which definitely requires prior consent from the originator.
So you can make the argument that publishing the image forms part of a publisher's content proposition from which they benefit (more viewers, more magazine sales or whatever). But you can make the same argument for twitter itself: twitter's value and the wealth of it's owners is derived exclusively from content it's users post. So can a user claim compensation from twitter for the value it has derived from their posts?
The same argument applies to say StackOverflow. I've spent countless hours answering questions and helping people out. SO sell ads against this content, and my content drives search engine click-throughs. Do I have a claim against SO?
> But has anyone done that?
Good examples of paid-for TwitPic photos include pictures in the wake of the Haiti earthquake, or the pictures taken of the Boeing which emergency-landed in the Hudson.
> Whey would they pay, given that it's available anyway?
Because they have to—the user only relinquished part of her rights on the picture, namely distribution on the Twitter/TwitPic medium, not her entire rights. If you think that were the TOS to change, the users would still upload pictures, you're so very wrong—see the TwitPic debacle recently and how MobyPicture gained a few k users because they state in their TOS that they can't sell their users' pictures without prior agreement.
You seem to think that your analogy is good, but I don't think it is. Were a magazine to publish SO answers in a Q&A section in a paid magazine, I think SO would be subject to licensing fees. In that case, the relationship between SO and you is governed by their TOS. Check them out, you'll have your answer.
Gives them. If you're posting pictures on Twitter or putting comments on SO, you can hardly fault them for displaying those.
But when AP starts selling your twitter pictures or SO comments on its feed, it's a whole different bucket of filth, and a very, very different situation.
We're discussing the second case here, not "I put a comment on news.yc and news.yc displays it".