To be dobbed in to authorities for adding someone you don't know very well on facebook. Be it your boss, the police, principal of your school or (for younger users) parents. The mountjoyer believes they are being stalked.
"I added the waitress from the coffee shop on facebook and she mountjoyed me to the police"
"I added that council worker biatch on facebook and she mountjoyed to my boss. now i my boss thinks i'm an online stalker!"
Young boy: "I added janie from the second grade on facebook and she mountjoyed to her parents, who then mountjoyed to mine!"
Young friend: "that's totally gay and uncalled for"