To make it short. Pligg has a plugin called Spam Trigger
. This module uses a spam dictionary and whenever one of those words match than the submission will be flagged for moderation or automatically deleted ("Your story has been discarded due to your choice of words which appear on our anti-spam list").
Keep this in mind when you wondering how to increase your verification rate for Pligg and check if articles of your niche might be affected by this.