A party-goer share is position on a social network before he is going to party or to party-trippin' so that other people (usually strangers) who want to go to the same party can join him and party together.
It could be a kind of flash mob in which people can meet new friends in a public place to drink and have fun and then they go party all together.
One of the social networks to organize party mob is partytrotters.net
"Yo man! i want to party tonight but my friends have to study!"
" Let's do a PARTY MOB nigga! so we can party with some brand new bitches and motherfuckers!"