It’s called “sexting,” the practice of exchanging sexually explicit photos with another person or sending racy text messages via cell phone. Mirroring a trend in society at large, there is evidence that lots of Marines are doing it, though the Corps does not keep data on the social phenomenon nor is it directly addressed in the UCMJ. It’s not illegal and not everybody thinks it’s wrong. But some Marines have already felt the sting of having what they considered private messages go public and, to their horror and embarrassment, shared with their chain of command.  Careers have been ruined, marriages…