A person who will keep sending you snaps on Snapchat even after being left on delivered or read. Common variations include: (a) people who send snaps of a ceiling or other basic background with the word "streaks" overlaid, (b) people send the same snap to multiple people at once, (c) people who directly send you snaps they also post on their story, or (d) people who continue snapping you because they actually want to talk to you. If you reply to a snap factory, there is a high possibility that you are left on read
Friend 1: Did y'all add Jordan on Snapchat? She sends me every snap she posts on her story!
Friend 2: Bro you need to un-add her! She'll be a snap factory as long as she has Snapchat.
Similar to a throwback. A throwbefore is a reference to something that happened in a time before you were born.
Listening to Hobey by Mariah Carey is such a throwbefore. (If speaker was born after 1997)