http://reason.com/blog/show/127444.html

Flickr, the popular photo sharing site owned by Yahoo, took down Dutch photographer Maarten Dors’ pictures of a Romanian teenage boy smoking a cigarette, arguing that it broke the site’s rules for appropriate photos. Dors says he didn’t intend to glorify smoking, but to document the living conditions in one of Eastern Europe’s less prosperous countries. Someone from Yahoo put the photo back on Dors’ profile, but another employee who was unfamiliar with the exception took it down a few months later. Someone else later put the picture back up, and it's still there, for now.

Dors’ stor is a reminder that ever-increasing usability has been accompanied by the de-liberalizing of user rights. Jonathan Zittrain, a professor of Internet governance and regulation at Oxford University, warns against Internet users relying too heavily on applications and software over which they have little or no control.

Here, from the same article, this is how Yahoo! explains itself.

While mindful of free speech and other rights, Yahoo and other companies say they must craft and enforce guidelines that go beyond legal requirements to protect their brands and foster safe, enjoyable communities—ones where minors may be roaming.

Guidelines help "engender a positive community experience," one to which users will want to return, said Anne Toth, Yahoo's vice president for policy.

go beyond legal requirements to protect their brands not that this is surprising, but it's rarely stated that bluntly.