In addition to murder, intrigue, and thrilling scenes of investigative journalism, State of Play, which opened last weekend, offers something novel: a credulous, reverent portrait of a blogger (played by Rachel McAdams, opposite Russell Crowe). More often, television and cinema have shown these history-altering media mavericks as somehow lacking in discretion, valor, and/or comprehensive personal hygiene. But if you study our brief history of bloggers in movies and on TV, you’ll see that some credit has been given where it is due — until now, finally, they are properly played as gorgeous crusaders with plenty of time and income for questing after deeply buried truths.