A load of random numbers & letters like a code, in yellow. I've seen the same on Yiff.Party. No I'm not an interweb clever-clogs so I sometimes ask these noob questions :D

It's called a tripcode, it's used to verify the identity users.

Oh right, so its just a way of preventing other people claiming to be the same user, or so people can't accuse you of "samefagging"?

I should've put "can't accuse 2+ people of being a 'samefag'"

No, you can still pretend to be multiple people since you can generate as many tripcodes as you want. It's to prevent someone from impersonating you by using the same name. You need the same password to get the same tripcode.

Tripcodes supported
1MB size limit