If there is a user ID attached to a user, a discussion tends to become a criticizing game. On the other hand, under the anonymous system, even though your opinion/information is criticized, you don't know with whom to be upset. Also with a user ID, those who participate in the site for a long time tend to have authority, and it becomes difficult for a user to disagree with them. Under a perfectly anonymous system, "it's boring", you can say, if it is actually boring. All information is treated equally; only an accurate argument will work.
>>1 Waaaah! I'm too upset with user Bread Ocreama, or whatever his fuckin' name is, so I'll start talkin' about HIM, like a little fuckin' pansy-assed sissy girl would! WAAAAAAAH! FIXED.