What does AIM snipe mean?

AIM snipe meaning in Urban Dictionary

whenever you deliver a person a note over AOL Instant Messenger (or any other IM solution), and it causes them to deliver half whatever they had been in the center of typing for your requirements in an email. Additionally familiar with describe once the "your buddy is typing" signal pops up immediately upon sending an email, meaning that the text typed in the IM box is not actually available.