Avatar should be obvious, because its from one of the few books I think everyone should be required to read. Well, the movie version since the book doesn't have oictures, but the reference should be obvious.
The name is actually less obvious. I didn't get the name from that Kubla Khan poem. I got it from an anime called, "Serial Experiments Lain", where a project called Xanadu, referencing the poem, was a significant plot point. I was a massive anime fan in high school, when I first started using the internet and needed a proper handle. Also, I realize that putting the year of your birth after a name has fallen out of style, but I find it useful to know the age of a person im talking too, and want to return the favor. I like not having to deal with people who disagree with me accusing me of being a child or something: Having my birth year lets people know that I remember 9/11, don't really remember the end of the cold war, and am an adult. Saves a little time.