We have a fairly fixed idea of intellectual property ó there's a gate and a name-plate around your imaginative labour. When you write something professionally, in return for your creative work, you expect regard and remuneration.
But what explains that weird tribe of people who choose anonymity instead? In times where much of your work goes into buffing your brand and making sure you're remembered, it seems crazy to deliberately evade attention unless you're hiding something.
We tend to forget that this attachment to authorship is a 20th century thing, that for most of our history, it seemed perfectly natural to simply create without affixing your name to it. That seems unimaginable now, in a situation where money rides on a reader's interest in a particular writer.
But much of the world's best artistic work has been done by Anon. Many of our splendid old stories are just there, epic, nested narratives composed across the years. Medieval art or songs didn't come with signatures either, because it didn't matter. The point is the story, not the storyteller. You were just a conduit, a channel for that extraordinary work. It was not a given that you had to trumpet your identity as author. Jane Austen's books were signed, simply, by "A Lady".
Up to the 19th century, reviews tended to be anonymous. (Even now, there is a debate on academic peer-reviewing, whether it is better to hide the name of the author when you send a work to be vetted, or whether an open system leads to better results).
Many of the important things that surround you are still the work of anonymous minds and hands. A recipe, an antique table, a jet engine, a life-saving drug, the software you use, they rarely come with signatures. But with literary and artistic works, we tend to search for the name. Someone like Banksy, the British graffiti artist whose real identity is still secret despite widespread public admiration, puzzles us. What motivates these folks to make a raid on our consciousness, if they don't want the attendant benefits of celebrity?