In the history of hashtag usage, the award for biggest understatement would have to go to Olivia Middleton for her use of #uhoh in the above tweet.

According to this and countless other jubilent, near-celebratory tweets by U of I students, a teacher's assistant for a math class, ie. the person who has to spend way more time dealing with the students than the professor who probably shows up for five classes a semester, accidentally sent the entire class a file containing images from a chat session featuring herself and her boyfriend engaged in various states of "Oh shit, I hope this never gets emailed to all the 18-to-22-year-olds I have to see everyday!"

Sources: Total Frat Move | H/T Gawker