From the article:
The F.D.A. warns against purchasing the drugs from online vendors, but women in the United States are doing it anyway. Increasingly, advocates of access to the drugs say, women are turning to the internet to procure the pills for use in their homes.
Plan B, a form of emergency contraception made available over the counter in 2013. Plan C piggybacks on that popularity, and hints at how the pills can be used: not necessarily after a pregnancy is certain, but as a medicine a woman can take if she misses her period, without being sure of the reason. In other words, just in case.