If there's good news about these sorts of cases, it's that they're often among the easiest types of Facebook troubles to deal with. The site makes it easy to report these kinds of abuse and easier still to block people from contacting you via the site (something I neglected to do, which is how he was able to send me a message).
There's an unfortunate loophole, though, that can make things much worse. Many people (including the woman Oates is accused of threatening) list their cell phone number or home number on their profiles—and Facebook has no control over how people use that.
In Knoxville, Tennessee, a woman whose name was similar to a person suspected of child abuse, received dozens of threatening calls from strangers who found her number via Facebook. (She was not related to the suspect and lives in a different county.)
As frightening as harassment can be, there are much worse things that can happen through the social network. Prostitutes and drug dealers use Facebook as bases of operation – and child molesters have found victims through the site's chat function. (Exactly how often this happens is hard to say. CNBC.com made multiple inquiries to the FBI and Justice Department about the frequency of Facebook-related crimes, but neither agency responded to the inquiries.)
On some levels, the criminal activity is to be expected. With 900 million members, Facebook is bound to attract a percentage of unsavory ones. Realizing this, the site formed a proactive security team years ago to watch out for hackers, pedophiles, and potential identity thieves and weed out objectionable (and illegal) images. It's currently headed by a former federal prosecutor for a U.S. Attorneys' office.
The security group doesn't seek the spotlight, though. A Facebook spokesperson, when asked about how the site handles potential criminal activity, referred me to the site's Safety Center pages.
No matter how thorough Facebook's screening is, some things slip through. And some of them are bad.
In February, Danish citizen Kai Lundstroem Pedersen, 61, was sentenced to 30 years in prison for producing and transporting child pornography and for extortion against an 11-year-old Missouri girl. He met his victims by creating a fake Facebook account where he posed as a juvenile male, convincing them to do sexually explicit acts in a video Web chat, which he recorded and distributed.
Earlier this month, the Justice Department secured a four-year sentence for a California man – James Dale Brown—for attempting to extort sexually graphic images from a 14-year-old.
Meanwhile, as Craig's List has cracked down on prostitutes advertising their services, tech-savvy hookers have turned to Facebook to attract johns.
Sudhir Venkatesh, a professor of sociology at Columbia University in New York, spent 12 months studying how prostitutes are finding clients these days, following 290 women and asking them about past and present practices.
"Even before the crackdown on the [Craig's List] adult-services section, sex workers were turning to Facebook," he wrote in early 2011. "83 percent have a Facebook page, and I estimate that by the end of 2011, Facebook will be the leading online recruitment space."
Generally, Facebook troubles are more personal, though – like what I went through. Last year, for example, two preteen girls hacked into a classmate's Facebook page, posting sexually explicit photos on her wall after they had a fight. They had gotten access to her account when she logged into Facebook at one of the other girl's houses earlier in the day.
A 2011 study by the Pew Research Center found that Facebook users are more trusting of other people than non-users.
"A Facebook user who uses the site multiple times per day is 43 percent more likely than other internet users and more than three times as likely as non-internet users to feel that most people can be trusted," it found.
(A new AP-CNBC poll released Tuesday, however, found that Facebook users cast a wary and suspicious eye on the platform itself: 59 percent of respondents said that they had little to no trust in Facebook to keep their information private.)
Too much trust of others may open the door for scammers and viruses. In January, security company ZoneAlarm issued a report finding that 20 percent of news link feeds open viruses – and four million Facebook users are exposed to spam per day.
Social networking can be fun—and a great way to stay in touch with friends. But just like anywhere else on the Internet, it pays to be on your guard.