Over the years, novelist Neal Stephenson (wiki), has had at least a couple different pages where he's explained why he's chosen to limit the access he provides via email, interviews, and phone calls. It appears to be something he's given a lot of thought to.

Via Jessamyn, here's an Archive.org mirror of an older version of his page where he explains his introversion and need to stay focused on his work, alongside FAQs that answer many of the questions he typically has to field. Read it all though. It's pretty good. Stephenson's bottom line?

I simply cannot respond to all incoming stimuli unless I retire from writing novels. And I don't wish to retire at this time.

And here's another well known piece, Stephenson's "Why I am a Bad Correspondent", in which he lays out more details about why he's chosen to create an expectation based on guarding his attention so slavishly:

Writing novels is hard, and requires vast, unbroken slabs of time. Four quiet hours is a resource that I can put to good use. Two slabs of time, each two hours long, might add up to the same four hours, but are not nearly as productive as an unbroken four. If I know that I am going to be interrupted, I can't concentrate, and if I suspect that I might be interrupted, I can't do anything at all. Likewise, several consecutive days with four-hour time-slabs in them give me a stretch of time in which I can write a decent book chapter, but the same number of hours spread out across a few weeks, with interruptions in between them, are nearly useless.

He closes with a practical summation of why he's made the decisions he has:

I am not proud of the fact that some of my e-mail goes unanswered as a result. It is never my intention to be rude or to give well-meaning readers the cold shoulder. If I were a commercial best-seller, I would have enough money to hire a staff to look after my correspondence. As it is, my books are bought by enough people to provide me with a sort of middle-class lifestyle, but not enough to hire employees, and so I am faced with a stark choice between being a bad correspondent and being a good novelist. I am trying to be a good novelist, and hoping that people will forgive me for being a bad correspondent.

As I read all this, I hear a man saying (at least in my words), "I can either be a guy who writes novels, or I can be a guy who answers email. Realizing I cannot be both, I've made the decision, and now I live with it."

Like it or hate it, Neal Stephenson's position is clear and well-articulated. If a bit pitched, it's a stance I admire, and frankly I think it's an only slightly more extreme version of a position every maker needs to define if he or she expects to create the time to keep making anything.