Politico's Dylan Byers reported Tuesday this was done at the request of the White House:
The AFP page for the story now links to a story titled "Senegal music star Youssou Ndour hits campaign trail," as does the Yahoo page. The Huffington Post page now links directly back to the Huffington Post homepage. The Daily Mail, Telegraph, and Australian stories now lead to 404 error pages, reading "page not found."
In an update, Byers explained who was responsible for the scrubbing:
Kristina Schake, Communications Director to the First Lady, emails to confirm this was a White House effort:
From the beginning of the administration, the White House has asked news outlets not to report on or photograph the Obama children when they are not with their parents and there is no vital news interest. We have reminded outlets of this request in order to protect the privacy and security of these girls.
Must be nice to command such an obedient media.