After joining in a riot or other illegal mass activity, you get busted because the police and other investigators picked out your mug shot from a myriad of facebook and youtube videos taken from mobile devices.

This is in reference to the St. Patrick's Day Riots at U Albany, 2011, where the police and school officials were able to identify multiple students through various youtube videos uploaded by others involved in the riot

A portmanteau of carpe diem, a Latin phrase that means “Seize the Day!” and DM, which stands for Direct Messages. This word means seizing the day via DMs.