There is a new link when looking at a photo page: Flag this photo as “may offend”.

From time to time, some images which are not appropriate for all viewers get uploaded into Flickr, made public, and show up on public pages. But that’s no good. So, if you click this link to flag a photo, it will be noted and some complicated computations will be done. Images which have been flagged by the owner or enough of the non-owners will not show up in public views.