A technique for tracking one or more thresholds relating to the blocking of a particular screen name used on an IM system is disclosed. If the number of people who have blocked a particular screen name reaches a threshold amount, a determination is made that the screen name is being used by a spimmer or other bothersome person, and disciplinary action can be taken. In a preferred embodiment, the email address associated with a user name of a suspected spimmer is identified and all screen names associated with that email address are also subjected to disciplinary action, if desired. Thus, an IM company can suspend all screen names of a spimmer that are tied to the same email address, even though not all (or even none) of the screen names individually have reached a threshold level for discipline/suspension.