A man sells surveillance cameras at the main electronics market in Tienhe district, Guangzhou, in southern China's Guangdong province, on Aug. 8. EPA /Landov hide caption

itoggle caption EPA /Landov

Palo Alto High School teacher Esther Wojcicki helps student Allison Wyndham at a computer during class. George Nikitin/AP hide caption

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The use of security cameras such as these, looking out over Tiananmen Square in Beijing, is on the rise in China. Critics say the government is using them to discourage dissidents. Ed Jones /AFP/Getty Images hide caption

itoggle caption Ed Jones /AFP/Getty Images

Nkomo Morris, a teacher at Brooklyn's Art and Media High School, works on her classroom computer in New York. Bebeto Matthews/AP hide caption

itoggle caption Bebeto Matthews/AP

Data gleaned from e-readers gives writers a new kind of feedback to take into consideration — or ignore. iStockphoto.com hide caption

itoggle caption iStockphoto.com