When one person in a group checks their smartphone and incites a domino effect of everybody else checking their own phones, thus ending all live discussion.
Andy caused a smartphone waterfall when he checked his email, so nobody noticed the 8 foot juggling clown that danced through the room while balancing on a beach ball.
When a bunch of people get together to party but eventually end up staring at their smartphones.
Alex: Hey, Jamie's throwing a party this Saturday! He's invited us all!
Jerry: Uh, I don't know...I'm afraid it will turn out to be a "smartphone party"...
Alex: He said it is going to be "unplugged" so smartphones are not allowed.
Jerry: Fuck no, Alex!
The act of walking slowly or "shuffling" because you're too preoccupied with tasks being done on your smartphone such as browsing the internet, texting, etc.
The Smartphone Shuffle can sometimes be dangerous for oneself, such as crossing a roads, not paying attention to surroundings. It can also be a nuisance for other people as distracted Smartphone Shufflers block hallways, stairs or sidewalks and impede flow of pedestrian.