In the sense as "to scatter trash"; to post, share, or perpetuate chain letters, hoaxes, or other internet "garbage", esp. knowingly sharing something that is stupid or misleading.
"Hey that thing you posted is a spammy hoax chain letter"
"Yeah, I know, I was bored."
"You're littering that bullshit all over everyone's feed."
"Sorry"
When someone goes after younger girls (and sometimes boys) with sexual intentions. Listers also are often found by your local hardcourt spying on prey while reciting to himself about Chechnyan warriors while using there Bluejay-like mating call to attract prey.
Person 1: Hey mate, I think I can see Jono Listering over there by the hardcourt
Person 2: He's such a freak for Listering