If you've been using internet slang on Twitter, be warned: the FBI is onto you. In fact, it's produced an 83-page dossier of "Twitter shorthand" so its agents can better decipher WTF all you cool kids slash potential terrorists are tweeting about. 

The FBI has so far compiled about 2,800 entries which range from the painfully obvious (YOLO, ROFL, BRB), the potentially incriminating (GAC - guilty as charged) to the bizarre (GD&R - grinning, ducking and running). 

According to the introduction to the list, the document was put together by the Intelligence Research Support Unit, which suggests to FBI agents that the dictionary may be useful in "your work or for keeping up with your children". 

The list was obtained through a Freedom of Information request on Muckrock, an organisation that helps the public to acquire data from the US government. 

If you would like to read the list (or send it to your elderly grandmother), it's below:

FBI Twitter List