Login names are coloured by user group. These are set in the software 'preferences'. I can't remember any particular reason why I used the colours I did when I set this aspect of the software up. They can be easily changed.

If you are in the $ Contributor's user group (you have financially contributed, which I very much appreciate) and on my computer it renders as an orange-gold. Technically $ Contributors names are This color - FF6600

Registered but Awaiting their Email Confirmation - #CC0000
Registered - #663300
Involved - Post Access - #330099
Courtesy Access - #006600
$ Contributors - FF6600

NOTE: Some Moderators are Contributors so if you see someone you know is a Moderator and is the Contributor color, it's because the $ Contributor colour is over-riding the Moderator 'user class' as far as the name colour goes.

Moderators - #006600
Super Moderators - #660000
Administrators - #990000

Those are the majors.

Check out:

http://www.kencole.org/et2assgn6.html (a grade school course!)
and
http://www.the-eggman.com/seminars/color_codes.html
and
http://www.tedmontgomery.com/tutorial/colors.html

For a bit more on user groups, see this post (http://elsmar.com/Forums/showpost.php?p=195275&postcount=19).