Five years ago, when Twitter was just another start-up and the iPad was a gleam in Steve Jobs’s eye, the state of print book reviews in this country was undergoing a spectacular and noisy collapse. Newspapers that were failing financially killed off their stand-alone print book sections, or folded them into the entertainment, ideas, or culture sections. They fired staff book editors and critics and cut freelance budgets. Hundreds of newspapers shut down altogether. Many magazines stopped covering books, and the literary quarterlies, for decades the champions of poetry and literary fiction published by independent presses, faced funding challenges as well.