When tragedy strikes America, Twitter remembers bad reporting.

Think back to Newtown. Within hours of the massacre in Connecticut that claimed the lives of 20 elementary school children and six adults, the news media had passed along a full story’s worth of erroneous information. We heard conflicting stories about whether the shooter, Adam Lanza, had entered Sandy Hook Elementary School by force or whether he was buzzed in. We heard that his mother, Nancy Lanza, was a teacher at the school. We also heard that Ryan Lanza, not his brother, Adam, was the shooter.

Around 3 p.m. today, a pair of explosions, within seconds of each other, went off near the finish line of the Boston Marathon. As of this writing, it’s unclear exactly what happened here, though a participant in the race speculated about “shrapnel” coming from one of the blasts. (The latest developments are being reported on the Early Lead blog.)

As if the media needed any reminder not to jump to conclusions about what was happening on the ground in Boston, Twitter came to the rescue, with numerous folks pleading for caution. Have a look:

There’s a lot more of this stuff out there, setting up an interesting social-media juxtaposition: The platform that’s most effective at churning out breaking news has become a place that preaches caution in breaking-news scenarios. Just in case editors and reporters need any reminders.