Red & Black usernames?

I have been wondering for some time, and I cannot contain my curiosity any longer:
Some usernames are black, others are red, what's the difference.

(I'm not talking about the bright red Administrator usergroup, but dark red normal users)
Uhm, after checking few threads, it seems that who started the thread is displayed as black.

No, I'm wrong
The "black" users belong to the "Just registered" users group, whereas "red" ones belong to the "Regulars" user group. The difference is that "Just registered" are promoted after that specific conditions are met to "Regulars", who are able to edit their posts....
I just cleared up my thread question, its not the colors but if a link or man page is Underlined it can be a link to an answer but can it be used to redirect without the readers/answerers knowledge?
Can someone explain the philosophy behind not being able to edit posts until you are "approved" or whatever.
This is an anti-spam measure to keep out spammers who post a few seemingly valid posts just to come back later and edit them to replace the contents with spam and spam links. By requiring a certain number of posts it is thought that those 'comeback and edit' spammers will move along because there is no quick spam run possible. Moreover, the more 'seemingly valid' posts are required, the more trouble a spammer will have to come up with content that doesn't set off alarms.