Registered User
Description: a registered user
Extra privileges: can send PMs if postcount is 10 or greater
Notes: none

Member Title User (Member)
Description: someone that either by his own merit or automatic promotion has been gifted with the Member title
Extra privileges: can access the Member and special invite areas, including the mods available on the former. Can request access to the shoutbox.
Notes: you can apply for the Member title here. It's gained automatically if invited. It's the only one you can apply for.

Guest Coder (Guest Coder)
Description: someone who isn't putting their coding skills at SB-I's service directly, yet wishes to have them acknowledged
Extra privileges: +Member
Notes: if you comply with the requirements, just ask a staff member

Advanced User (Advanced User)
Description: someone whose contribution to the board has a cut above other users', something the staff wishes to acknowledge
Extra privileges: Member+full shoutbox access+access to the beta mods+additional styles+extra privacy features
Notes:

Elite User (Elite)
Description: a long-standing, exceptionally contributing user
Extra privileges: Member+AdvancedUser+can access the Elite forums
Notes:

Retired Staff (Retired Staff)
Description: A former staff member who unfortunately had to step down from his position
Extra privileges: Member+AdvancedUser+Elite
Notes:

VIP (VIP)
Description: site founders, names with a long past in the leecher scene
Extra privileges: Member+AdvancedUser+Elite+moderation privileges (some of them)
Notes:

Coder (Coder)
Description: an individual with coding skills that actively participates in releasing and improving SB-I mods and tools
Extra privileges: Member+AdvancedUser+Elite+can access the coding forums
Notes:

Moderator (Moderator)
Description: someone in charge of enforcing the forum rules
Extra privileges: Member+AdvancedUser+Elite+Coder+Moderation
Notes: causes the What.cd staff not to like you

Special classes

SB-Innovation Bot (Bot (Please don't reply))
Description: tells users what they did wrong, facilitates certain moderation tasks
Extra privileges: can't be added as friend
Note: you can't get this title

Banned (Banned, may not be visible)
Description: someone with a severe rule-violation record (spamming, having multiple accounts) the staff wishes to separate from the forum
Extra privileges: can't do anything
Notes: use this if you're banned and wish to plead your case. Bear in mind obvious, stupid excuses are only a waste of time for both parties.

Unregistered
Description: self-explanatory
Extra privileges: can't do anything that alters the database
Notes: register or log in

Users Awaiting Email Confirmation
Description: self-explanatory
Extra privileges: can't post nor PM
Notes: activate the account and get this over with. Please use the Contact Us form instead of creating a new one if you haven't received the e-mail.

Inactive Users
Description: self-explanatory
Extra privileges: can't do anything
Notes: gets reactivated upon logging in