In Second Life, you have:

• A username, your unique Second Life account name that you choose when you register your account.  Once chosen, you cannot change your username.
• A display name shown to others inworld and on your profile.  You can change your display name as often as once a week.  In addition, you can always reset it to its default, your username.

Your username and your display name are totally separate.  If you haven't set a display name, then it defaults to your username.

Usernames

Your username is the unique account name or account ID you use to log into Second Life. By default, it appears above your avatar inworld and identifies you to other Second Life Residents. You can also set a display name that appears above your username.

The format of your username depends on when you registered the account

In 2010, Second Life changed from registering new accounts with a "first name" and "last name" to a single-word username  If you registered your account after mid-2010, you created a unique, single-word username; for example: mortimer1980, or jsmith57.  When you log in to Second Life, you simply enter the  username you selected when you registered. 

If you created your Second Life account before mid-2010, you have a Second Life "first name" and "last name" that determine your username as follows: firstname.lastname.  For example, if your Second Life name was originally Joe Smith when you joined, your username is joe.smith.

Your username is a unique and personal account identifier in Second Life, and as such, once you choose it you cannot change it.  

Logging in with your username

The official Second Life Viewer requires a single username. However, some third-party viewers still have fields for a first name and a last name.

Using a Viewer with separate first and last Name login fields

If you are a newer Second Life Resident with a single-word username:

1. Enter your username in the First Name field.
2. Enter resident in the Last Name field.

For example, if your username is thejoesmith, enter:
 

If you are a longtime Second Life Resident with both a first and last name, simply enter your first name and last name in the corresponding fields.

For example, if your Second Life name is Joe Smith, enter:

Using a Viewer with a single name login field

If you are a Second Life Resident with a single-word username, simply enter that username along with your password and log in as usual.

If you are an older Second Life Resident who has a first and last name, you have two options:

• Enter your original first and last name (in lowercase, separated by a period) into the field provided OR
• Enter your original first and last name separated by a space (case does not matter).

For example, if your SL name is David Dearheart:
Username:

• david.dearheart
  OR 
• david dearheart
  OR 
• David Dearheart

Then enter your password into the Password field and log in.

Showing or hiding others' usernames

You can't control the display of your username to other Residents, but you can control whether you see others' usernames and whether you see your own name.

To show or hide usernames inworld, both above other avatars and in chat:

1. Log into Second Life.
2. Choose Me > Preferences from the top menu.
3. Click the General tab.
4. Select the Usernames checkbox. If the box is checked, usernames are shown. If the box is not checked, usernames are hidden.
5. Click OK.

A club scene showing usernames and display names is illustrated at left.  In this image, some usernames are blurred.  Notice that only the username is shown above avatars who haven't set a display name.

Display names

Your display name is:

• A name you choose shown to other avatars in the Second Life virtual world.
• A string of charactersup to 31 characters long  that contains at least one alphanumeric character. It can include most Unicode script characters, spaces, and some punctuation.
• Distinct from the username you use to log in. 
• Not necessarily unique; other avatars may have the same display name as you.

You can choose whether or not to show other Residents' display names and usernames inworld. If you choose to view display names or usernames, they appear in the name tags above every avatar and in chat.

Allowed characters

In addition to letters and numbers, you can use the following characters in your display name:

• ' (apostrophe)
• - (hyphen-minus)
• . (full stop)
• : (colon)
• · (middle dot)
• ֊ ֊  (Armenian hyphen)
•  (Hebrew geresh)
• ״ (Hebrew gershayim)
• ་ (Tibetan tsheg)
• - (hyphen)
• ’ (right single quotation mark)
• ‧ (hyphenation point)
• = (katakana-hiragana double hyphen)
• · (katakana middle dot)

Setting or changing your display name

You can change your display name once every seven days, but you can Reset it at any time, which makes it appear as your "classic" Second Life first name and last name, or your username.

To set or change your display name:

1. Log into Second Life.
2. In the Second Life Viewer, click Me > Profile... or  in the toolbar.
3. Click Edit Profile.
4. Click Display Name.
5. Type the desired display name in the field under New Display Name.
6. Type the name again to confirm.
7. Click Save.

Showing or hiding others' display names

To show or hide display names inworld, both in chat and over all avatars:

1. Log into Second Life.
2. Choose Me > Preferences from the top menu.
3. Click the General tab.
4. Select the View Display Names checkbox. If the box is checked, display names are shown. If the box is unchecked, display names are hidden.
5. Click OK.

Information for content creators and merchants

Both username and display name are visible on objects

Object properties and build tools show both the username and the display name of an object's owner and creator. During Linden dollar and other transactions, both your username and display name are visible.

Display names on objects change when you change your display name, although it may take up to one day for the change to appear everywhere. 

Username is shown in transaction history

Your transaction history shows only usernames for both buyers and sellers.

Search covers both usernames and display names

When you search for a Resident, search results contain both display names and usernames so that you can easily determine which John Smith you're really looking for.

If customers know your username, don't set your display name to avoid confusion

To emphasize your username, don't set your display name; this way your display name and username match. As a precaution, you may also advise your customers that they should only pay avatars/objects matching your username.

LSL uses only "full name" derived from username

LSL functions return the "full name". For example:

• Username: kelly.linden
• Full name: Kelly Linden
• Display Name: Teh Kellz

For more information, see LSL Avatar/Name in the Second Life Wiki.