#2 Sep 25, 2004 00:11
It's not a feature as far as I know. Anyone who can see a post can comment IF comments are not closed or disabled. Closing or disabling will also affect registered bloggers, so that's not what you seek. It's an easy hack if you don't mind going down that path, but the hack will affect all posts under all circumstances - you won't be able to say "posts in this blog can be publicly seen and commented, but posts in that blog can be publicly seen but not commented. Also, it will not over-ride the closed or disabled condition.
Every skin has a skinname, and every skins/skinname/ folder has a bunch of files in it. The skins/ folder tends to have the same file names. Open skins/_feedback.php and look down around line 140 for this
Save the file and upload it. Live long and prosper.
Be aware I have not actually done this. It just seemed like a pretty straightforward hack.