Here's one use of Facebook that CEO Mark Zukerberg probably didn't foresee: some birth relatives and their adopted children are making contact with each other through the global social network.
It's a development that has concerned some psychologists, who fear the destabilizing impact that kind of sudden contact could have.
In Britain, health services fear that some birth parents — and in particular those who may have been abusive in the past — could track down their birth children via sites like Facebook to establish or re-establish contact. Some psychologists have reported that adopted children have displayed troubled behavior after their parents had unexpectedly re-established contact.
According to a report in the Irish Examiner, the Adoption Authority of Ireland (AAI) has said there is already "anecdotal" evidence that birth relatives and adopted children have contacted each other via Facebook, but the outcomes to date do not appear to have been negative.
But in a sign of the times, the AAI revealed there had been cases where someone who had been adopted had traced their birth relative on Facebook and made contact within 20 minutes.
Nowadays, however, many agencies operate what they call a "clean break" adoption procedure, which means that birth relatives are less likely to have been given the adopted name of their child, hampering a search later on, and equally a parent who adopts may be provided with little information about the identity of the birth parents.
In Ireland, there is no automatic access to birth files for those who have been adopted, which means that anyone seeking a relative online may only have a first name with which to start.