Of course the facile answer is that it is a combination of "Anders" and "Art".
This website is a part of an artwork, where I am both artist, artwork and its subject. Everything I do is a part of my artwork, which encompasses the whole of my life. It is a kind of automorph art genre: "the Extropic Art of consciously and comprehensively sculpting one's psychology and physiology. Art as Being. One's extropic self-transformation, both mentally and physically." Natasha Vita-More, Transhumanist Art Statement 2.0
On another level it is a childhood memory.
When I was about 12-13 years old I began the project of creating my own big science fiction universe. I already had one that emerged out of my earlier games and stories, but this time I was ambitious. I wanted to write a book about the adventures of someone in this setting, an entire galaxy of planets inhabited by strange aliens and unusual science. Note the word of 'someone' - I never got the hang of who was the protagonist and was rather uninterested in the question. He was an unimportant character whose only merit was that he was constantly asking about the food, furniture, society and science of the future so other characters could fill him in. The real protagonist of the novel was of course to be the grand setting. I think most science fiction readers know this situation. There are uncountable novels where this happens. Sometimes the result is good, usually mediocre. Fortunately for the bookshelves of mankind my novel of course never got off the ground.
I realized that to keep track of the hundreds of planets I needed for the setting (it was, after all, an entire galaxy) I needed to write down essential information. So I got myself a big notebook and started to fill it. The first planet was Andart 5. If I recall right it was a mostly airless ball of rock orbiting a reddish M star somewhere in the remote corners of the galaxy, an important industrial center but frankly entirely uninteresting. But I had realized that in a vast galaxy there has to be plenty of these uninteresting places. So I had to add at least one of them. Andart 5 was my first real world, perhaps not very ambitious but still a first step in worldbuilding. Which was to become my main vice and pleasure ever since.
My name is Anders Sandberg. I'm a worldbuilder and proud of it.