Over the last three years, South Carolina prison officials have brought more than 400 disciplinary cases against inmates for "social networking," the Electronic Frontier Foundation reports. Penalties in such cases are exorbitant, including time in solitary confinement as well as deprivation of visitation and telephone privileges.

Following a request filed under South Carolina's Freedom of Information Act, the EFF identified at least three cases in which inmates received more time in "disciplinary detention" than they had actually been sentenced to serve in prison. Tyheem Henry, for example, received 37.5 years in solitary confinement and lost 74 years worth of telephone, visitation, and canteen privileges.

The EFF explains why the penalties are so severe:

The sentences are so long because SCDC issues a separate Level 1 violation for each day that an inmate accesses a social network. An inmate who posts five status updates over five days, would receive five separate Level 1 violations, while an inmate who posted 100 updates in one day would receive only one.

Henry, the South Carolina Department of Corrections said, will not have to serve the full 37.5 years of his punishment, as his actual sentence—between five and ten years—is shorter than that.

The report also found that SCDC staff members obtained inmate's passwords and used them to access inmates' accounts. Also, as part of an effort to catch inmates using the service, SCDC investigators created fake profiles. Both are violations of Facebook's Terms of Service.

Facebook—which denied to the EFF that it enforces prison policies—has a "Inmate Account Takedown Request" form. The EFF found that SCDC paid $12,500 to an outside contractor to assist in its investigations.

"We take the use of contraband cell phones and social media by inmates very seriously, and the punishment for using them is severe," SCDC director Bruce Stirling said in a statement, referencing a 2012 attack on a corrections officer coordinated via a contraband phone.