I've seen these letters as a BG on some HAs, what's that? What does it mean?

It means: No Victims Left Behind

Its in reference to biting people who want to get infected with specific strains.

See [topic not found]

No Victim Left Behind. It's a forum group (or I guess technically a set of forum groups since they have a separate ping for each zombie strain) that runs zombification threads to help other users get infected :)

Ooohhh...right, right, thanks :) And OMG you look SO cuuute! <3

Thanks, it showed after I posted :D

Thanks!