I can definitely see where credibility is of importance. You point to a great example. What is nice about Reddit is that you do have that option to remember names so that you can do exactly what you describe. Sometimes, subreddits will also take care of that with verified flairs, or alternatively, the user can go out of their way and use RES to make note of users they trust.
> I also dislike reddit because it's hard to remember a name constantly. It's easier when there's a little profile picture next to the name. You go, "oh yeah, that guy. He's helpful." You remember those posters more often.
To me, personally, I like Reddit because this kind of association is more difficult. I like reading a comment and not having any bias towards the user.