President Clinton used Washington's most recognizable set, the White House, to announce that most cinema owners had agreed to require young people to show photo IDs when they ask for tickets to R-rated movies (an R rating means those under 17 must be accompanied by a parent or adult guardian).

CNN: Taking aim at show biz

Blogging service Tumblr and photo-sharing service 500px have also seen their iPhone and iPad apps boosted to the maximum age rating over the past fortnight.

BBC: Twitter's Vine app gets adult rating on Apple store