One thing that seems to happen in Second Life on a very regular basis is the formation of more than one avatar.  There are many reasons for this -- some good and some nefarious.  Why do people form alts?  The reasons of those that I have met boil down to:

• multiple personalties -- each person requires a different account
• each facet of your personality requires a different expression -- even though you can change your look completely, it takes time!  And there are always factors with rezzing and lag when you try to switch no matter how carefully you have set up your appearance folders.  Maybe you just don't want to constantly switch from the adorable hatchie dragon to the imposing mer to the human child to the party person to the robot to the fae to the....  you get the idea!  
• role play -- your RP persona has different friends and groups than your main account
• business -- you need to have an alt that can build or socialize without being bothered by the responsibilities of your shop, for example

Who I am, from left to right, name and rezz dates:

1]  the one and only beladona Memorial 12.04.05 is the closest to being like the real me translated into pixels.  You can also learn about her on this older profile -- but SLBuzz hasn't been updated for a while now but the pictures are still all there.  The oldest picture is from November 2006.

2] kala 10.09.07, originally created specifically for my then partner in SL, Sam Holyoke, as elona Dayafter.   Her name?  well "alone" spelled backwards came out "enola" -- and that just sounded too much like a disease from the jungles, so I switched the consonants around and made it "elona".  Dayafter was available at that time, and a name that said something about being alone the day after seemed apropos at the time.  She became a kajira of Gor and it was through her that I met my third partner, Searaven Raymaker.

3] Ndlovukazi Noyes 10.15.07 was originally designed to help keep tabs on the alts of that same partner that elona was created for, but I immediately realized that wasn't a very trusting basis on which to keep our relaitonship going.   Instead, she became a playful kitten, hanging out in different Neko havens.   Her name?  Noyes was the name of the street where I was living at the time.  Ndlovukazi is Ndebele for "queen of the elephants" who must be treated with respect and caution  My dear friend gave that to me as a nickname.  Haven't met a person yet who can pronounce the name, which is why her group title says:  Call me Kazi

4] bela Martian 10.10.08 is one of the evil Martian overlord’s minions.   It was Razzup's rezz day ... oh, what is a rezz day?  That is the day you first come in world and start exploring your 2nd life!   The last name of "Martian" became available, and about 20 of us created alts for a special birthday bash for Razzup, who really was a little green man.

5] Mirabelle Mynx 02.08.10 –  Mira's first name was chosen for no better reason than it sounded good with the last name that I liked.  Why a kid avatar? because I like playing with the other kids. She actually spends most of her time in the different Disney sims and is a ward of the Order fo the FoxRose clan, but isn't quite tame.

6] Sahar Soulstar 02.10.10, Free Woman of Gor and daughter to Lucius Toxx, Chief Physician, twin sister to Rius.  I love her name, but this one I didn't choose -- the avatar was actually created by Lucius for role play and given to me when I agreed to take on the role.   We didn't get a chance to do much with it since the City of Venna closed.

7] Bela Enchanted 11.17.10 was an accident.  I thought I was signing in to the browser based beta. I had been told a new identity was assumed rather than being able to log in as an existing avi, so I blithely went all through the formation process, grabbing the name "Enchanted" and suddenly was totally perplexed to find myself landing on Orientation Island.  She is still forming her identity and her look and pretty much hasn't done anything but shop to date.