Nicole Eason, who Reuters reports was taking in children that were "advertised" on the Internet. Samantha Sais/Reuters For 18 months, Reuters investigative reporter Megan Twohey examined how American parents use the Internet to find new families for the children they regret adopting.

What she found was startling: parents were using message boards and forums on Yahoo and Facebook to pawn off their adoptive kin to virtual strangers in an informal (and often illegal) practice called "re-homing".

This morning, Reuters published the first in a five-part series on the topic called "The Child Exchange".

The series is made up of interviews with parents who gave away or took in children, the facilitators who aided in the process, and organizations that participated in re-homing. A team of Reuters investigative reporters also uncovered and analyzed more than 5,029 posts from one of the bulletin boards, a Yahoo group called Adopting-from-Disruption, and thousands of confidential documents from child welfare agencies.

Twohey also interviewed children themselves. Many of these kids were handed off strangers who physically, mentally, and sexually abused them.

The story uncovers an American black market for adopted children, Internet forums where ads are placed for kids as if they were old television sets.

"We adopted an 8-year-old girl from China…." read one ad. "Unfortunately, We are now struggling having been home for 5 days." The parent asked that others share the ad "with anyone you think may be interested."

Yahoo shut down Adopting-from-Disruption, as well as five other groups with similar objectives, once it learned of Reuters' findings. A spokeswoman for Yahoo said the groups violated its terms-of-service.

Though the Facebook group reported on within the series seems to be obsolete, it was still active at the time of publishing, according to Reuters.

A similar forum on Facebook, Way Stations of Love, remains active. A Facebook spokeswoman says the page shows "that the Internet is a reflection of society, and people are using it for all kinds of communications and to tackle all sorts of problems, including very complicated issues such as this one."

In partnership with Reuters, NBC News is featuring the series in segments on "NBC Nightly News" and the "TODAY Show". Reuters will publish the series in parts from today, September 9 through September 11 at reuters.com/investigates/adoption. You can also watch the "TODAY Show" segment that aired this morning here.