Amy Cuddy must be proud: Clay Shirky walks on stage and promptly strikes a power pose. Then he tells us of a 9-year-old Scottish girl who lives about 50 miles from here. Martha Payne started the foodblog NeverSeconds, for which she took her camera into school to document her lunches, using metrics such as “pieces of hair found in food.” First, she acquired dozens, then hundreds, then thousands of readers. Until, two weeks ago, when she posted that she’d been shut down by her head teacher. No more photos from the lunch room.