look at their plurk url type@ and then their name

like I would be ATwhimsywinx

@ = AT t

or if you are in a convo with them, hover tip to the right of their comment click the reply pop up to auto do it

@<name of the person

Atomic, I've had this question for the longest and just figured out today how to use it in another plurk (your not alone )

WhimsyWinx & ManuelOrmidale ty ty

BlairLeifstrom LOL