1. A person who you only email when you get one of those "Send this to 200,203 people in 10 minutes or your entire family will suffer fatal heart attacks!" You never email just to chat.
2. One of those "This will happen to you if you don't send this!" people featured in chain letters.
1. Girl 1: Ooh, look! Kevin emailed me!
Girl 2: Don't open it. You're chain letter scum to him.
2. "A girl named Martha Mowdry recieved this chain letter last April and ignored it. The next day, her whole family was killed in a freak plane crash, her house burned down, and she was diagnosed with kidney disease." In this situation, Martha Mowdry is "chain letter scum".