Just days after Twitter's video-sharing [3] site Vine [4] got into hot water for putting six seconds of X-rated footage up as an Editor's Pick [5], Tumblr [6] has added an R rating to its iOS app [7]. So, download version 3.2.4 of its app and you get a Blue window stating that "Tumblr contains age-restricted material," plus a box to click to confirm that you are over 17.

Perhaps this is a preventative measure to ensure it stays on the right side of Apple [8], whose App Store [9] nabobs wield whatever the cyber version of the black marker pen is [10] with gay abandon--Steve Jobs [11] claimed that the store offered "Freedom from porn [12]" in an email to Gawker writer Ryan Tate [13]. Perhaps it's one of those small gestures that acts as a semi-placator to parents, while acting as a metaphorical pair of red knickers to curious teenagers. Anyway, it's there now. Is it an attention-grabbing move to make Tumblr more attractive to a new audience--the site is, of course, now more popular [14] amongst teenagers than Facebook is--or do you think David Karp has shot himself in the nether regions with this move? Share all you want (but not too much, we like to stay classy) in the comments.

[Image by Flickr user joshwept [15]]