Originally referred solely to the practice of using a player's livestream to locate and kill them. This usage has expanded to apply to instances during in-real-life streams where a viewer will attempt to interact with the streamer whom they've located thanks to their stream.
The act of using a creator's live broadcast to find their exact location in a video game or real life to interact with them without their consent. While some snipers just want to quickly say hi to their favorite streamer, in a video game setting, it can be often used to gain an unfair competitive advantage or to grief the streamer.
Basically, a form of digital stalking with a funny name. While some communities treat it as a meme, others treat it with extreme caution. It can ruin the experience for the creator and the people watching.
"The streamer had to cut her broadcast and duck into a grocery store because a stream sniper used the street signs in her background stream sniping her."
"The streamer had to switch to a hidden account and put an overlay on his map because he couldn't play a single match without twenty people stream sniping hot-dropping on his location."
This is usually used when someone watches your/someone elses stream to get an advantage, or they try to get into their game to kill them.
They usually land on top of you (fortnite) or find your base.
It fucking sucks.
Ninja: *playing fortnite*
Ninja: *gets killed*
Ninja: dance.. dance.. THERE IT ISSS
*reports for stream-sniping*