I thought this question in the New York Times was interesting: Should a novelist write reviews? Zoe Heller and Adam Kirsch argue “yes” because such conversation about literature is a way to show that it matters. Kirsch adds:

For all these writers [Virginia Woolf, David Foster Wallace, Henry James], criticism was a way of understanding themselves, of discovering how they did and did not want to write. It was also a means of educating the public, preparing readers for the revolution in taste they wanted to sponsor. Perhaps a writer can’t be great without a touch of this kind of aggression, this intolerance of artistic error. At the very least, novelists who do risk writing criticism should know they’re in the best of company.