Demaestro - 9:17 pm on Nov 9, 2009 (gmt 0)

opt-in vs. opt-out

Yes but that issue has been decided in court already.

robots.txt file or noindex/nocache attributes, but those are certainly no guarantee.

These have to work otherwise the opt-out system would be called into question if one couldn't be guaranteed the ability to opt-out. If those methods don't guarantee your site not being indexed then Google is in legal trouble.

My guess is that Murdoch is trying to figure out how to get Google to stop indexing their content without removing their site from Google's search results.

He doesn't want to use the current removal techniques and he talks about Google not using his titles and content, but never outright says "I don't want my sites to appear in Google"