Old-timers will recall making regular calls to district stations to see what's going on. That practice has ended for many reporters. The Baltimore Sun's Justin Fenton gets a text tweet on his phone when a significant crime happens, usually within 20 minutes. “It’s like I’m a member of the command staff,” he says.

The system has limitations: tweets give the barest of details, and the Baltimore police Twitter stream shuts down at midnight. And Fenton says that when he reaches out to police for more information, he often hears, “What we tweeted is all we have.” All 140 characters of it.

> When crime victims tweet, new and old dilemmas meet for news outlets