Epistolary Novel

What do you think of epistolary novels? I read a recent one the other day and was of two minds. On the one hand, I enjoy the creativity behind a book composed of fictional letters, and the genre is as old as novels themselves. At the same time, how many people in real life write letters anymore?

I tried my hand at an epistolary novel once. I liked it, but several agents I met at a writer’s conference baulked at the idea of an epistolary novel. They’re very difficult to sell and rarely do well commercially. But I’m more concerned with this type of novel from an artistic point of few. Modern communication has changed so much, that a series of lengthy letters now seems archaic and difficult to related to in many ways.

So what do you think? Have epistolary novels had their day? Or is there hope for them in adapting them to the modern world?