Rin and my old username Nire are variations on my actual name: Erin. Back in high school my buddies started calling me Nire (pronouncing it as nee-ray) and so I use that for my name on many sites I frequent.
I switched to using Rin more recently, mainly because it sounds nicer.
I actually picked my name for my cam girl name. After going through so many of them. I had a couple of members say to me you are Just Like Heaven. After awhile it stuck with me. Then I came across something that said "Just Like Heaven everyone wants to get in". From there that was my new username for camming. Then I did not know there is a group called The Cure who have a song called JustLikeHeaven. I was on google making sure my name did not pop up all over the place and came across the song. I actually like it and the group The Cure. So now I use it a lot.