1. Steam Name?
I've been a big fan of Lloyd Alexander's The Chronicles of Prydain since I was in elementary school. From my first account on a local BBS in 1992, and in subsequent online communities (Westwood Online [playing a ton of Red Alert 2 on a 28k modem], GameSpy) my online name has always been Taran or some variant.
My current name came in 2000, when I made an account on zone.com to play Jedi Knight. Someone had already taken the Taran moniker, so I was forced to change my name. Hating the "triple-x" and "name-number" style of account names (which I thought were pretty garish), I simply decided to go for an extended version of what I already had. When I first created my Steam Account 4 years later*, I kept the name and it's been with me ever since.
It also has the added bonus of being able to determine, depending on the reaction to the name, both maturity and the ability to fully read consonants.
*JFC, my account turned 17 years old on April 18...
2. Character Name?
They usually come from one of two places.
The first set (Sarah Walker [LP], Cecilia Baker, Lomahongva, and Julia Grant) are composites of friends, family members, coworkers, or people who I'm reasonably familiar with on a day-to-day basis. The names of the people I reference are nowhere reflective of the personalities I play in-game.
The second set (Seong Myung-hwa, Kinley Tenzing, Lomahongva, Butach Nerguei, and Noriko Kubo) are based on a study of etymologies. I'm always on the lookout for names that fit my initial character sketch and their internal motivations.
3. Backstories?
It's a composite of fundamentals.
First are initial conditions - who makes up their immediate family, how close are the characters to their siblings and parents, what is the family like in public and behind closed doors, etc?
Second, are ethical convictions - how do they view other people, how do they rationalize their life during the day-to-day, and are they religious or do they believe in some other moral code?
Third is a look at the broader society in which they live - is there a kind of class/caste system in which they're pegged to, do they benefit from the society they were a part of, and are there any cultural mores or taboos that they to work with or live under?
Lastly is a general sketch of their last ten to fifteen years - when things started changing to the setting of the server, were they singled-out by the authorities, did they keep their head down, or did they have a skill or talent that might have drawn interest from some faceless bureaucrat?
From there, it's broader research into the culture of each character - although I'll only discuss three at the moment. In the case of Cecilia, it was a personal study into my own adolescence - complete with constant chafing against the quasi-caste system of the American Midwest. For Seong, it was based on hundreds of pages of testimony and oral histories of defectors from the DPRK, especially from Chongjin, and the average North Korean's sincere desire for unification with the South. And with Lomahongva, her story sprang from living on the edge of the Hopi reservation and being a caretaker for two of their most important migration sites - complete with discussion about the prophecies of the end of the Fourth World (the one which we inhabit) and the transition to the Fifth.