As you may have noticed, some members have their usernames coloured blue or grey, these are members that are either staff of vBulletin.nl or suspended (banned) users.

Administrators' names will be seen like this:
Username

Moderators and Super Moderators' names will be seen like this:
Username

Suspended (banned) users
You may also see some members with grey usernames, like this:
Username
These are users with suspended (or banned) accounts.

Hope this clears a few things up. :)

Even better, if you now hover your mouse over a username, it will popup the usergroup_title ; so it is very clear which member is in which usergroup. This works on the whois online, the threads, etc. Enjoy :)