The act of being annoyed with someone through a social network and deciding to "virtually spit" on them, without the disgusting nature of the act in real life.
"Dude, Mike was totally being a douche on Facebook, so I just spit on him"
"You spit on him?"
"Yes, virtual spit, it's the latest craze. The kids are hopping and popping on their computers, ejecting disgusting virtual spit out of their virtual mouths"
"It's like a poke, but with hostility. I have waited all my life for this."
Just learning about the concept of virtual spit drives people to end war and in exchange for the less destructive virtual spitting.