Wasn’t it just the other day that teachers confiscated cellphones and principals warned about oversharing on MySpace? Now, Erin Olson, an English teacher in Sioux Rapids, Iowa, is among a small but growing cadre of educators trying to exploit Twitter-like technology to enhance classroom discussion, reports the New York Times. Last Friday, as some of her 11th graders read aloud from a poem called “To the Lady,” which ponders why bystanders do not intervene to stop injustice, others kept up a running commentary on their laptops…