On a hot afternoon in New York City, my friend Miriam was sitting at a grassy public venue, watching her child play alongside other kids in the care of various moms and nannies.

A long-time New York resident, Miriam is fully aware of the city’s urban imperative: mind your own business.

But she couldn’t help but notice the crying of a nearby baby, approximately nine months old, strapped in his stroller facing the sun, while his nanny ignored him and chatted with another nanny.

The minutes passed…5…10…15…the baby’s skin got redder, the crying persisted, and the nanny’s only response was to periodically bark, “Shh! Be quiet!” while brusquely shaking the baby’s stroller.

And that is when Miriam decided she had to do something: she had to stop minding her own business.

In New York, where the number of scary nanny stories surpasses the number of scary subway stories, an increasing number of citizens are posting reports about bad nanny behavior on a blog called I Saw Your Nanny.

The posts—complete with date, time, location, physical descriptions of nanny and child, and sometimes a cell phone photo—will stop the heart of any parent who recognizes his or her nanny or child: I saw your nanny …grabbing your boy by the ear and twisting him…mistreating and roughly handling your 3-5 year old girl…fell asleep right on the bench where she was sitting with her back to your son.

Launched in August 2006, the blog has sparked a debate about the obligations—and limits—of personal responsibility. Critics contend that it’s potentially libelous for strangers to publicly attack a nanny’s professional performance.

But that didn’t stop Miriam from confronting the nanny about the neglected baby. “She told me to mind my own business. Then she started yanking the baby in the stroller. That’s when I told her I was calling 911.”

Aware that NYPD was on its way, the nanny bolted to leave the location, still yelling, “Mind your own business!” Miriam ran ahead of the woman and snapped her picture with her cell phone. But by the time the police arrived, the nanny was gone.

Tell us what you think: When is it right to stop minding your own business and start minding someone else’s? How far would you go in reporting disturbing behavior by a nanny or anyone else?