The one issue I see with this is it is always Opt Out. I feel that google really should be lining up partners to opt-in. While I am sure there is reasons why Google believe they have the right (and a good case can be made), it always feels slightly entitled to just assume that people are OK with this being done to their content.
That being said, of all the sources, Wikipedia actively license their content in such a way that google are well within their rights to slurp it all down and serve it however they want.
Google is already effectively paying for links to news sites as part of the negotiations in Australia. And I agree that this will be a dampener on any competition, I think the era of "ask for forgiveness, rather then permission" needs to stop.
if you post information publicly on the internet, google is entitled to scrape it. you've opted in by publishing it.
if you want to specifically exclude one entity from accessing information that you've posted for anybody to see, i'm not sure how there's a way that could be "opt-in"
Google is entitled to scrape it, but are they entitled to display the content on their site, the results pages? Everything in the instant answers is content that deserves to be displayed on its creators page, along with whatever monetisation the creator chooses.
That being said, of all the sources, Wikipedia actively license their content in such a way that google are well within their rights to slurp it all down and serve it however they want.
Google is already effectively paying for links to news sites as part of the negotiations in Australia. And I agree that this will be a dampener on any competition, I think the era of "ask for forgiveness, rather then permission" needs to stop.