Of the three communications I've initiated with authors since writing the post above (one via US mail, two via author blogs), only Theo Pauline Nestor ("Writing Is My Drink") responded directly. And though her response was wisely terse, it felt sincere.
Soon after re-reading my post, I realized my public "confession" three years ago about unsent letters acted as a catalyst and gave me permission to do something I'd long resisted, i.e. telling an artist what their work has meant to me. The letter I sent to author Amy Bloom about her novel "Away" is dated June 2, 2011. Later in the year I also contacted Nina Sankovitch ("Tolstoy and The Purple Chair") via her blog, attaching my post (below) about her remarkable memoir, which had assisted me to climb out of a serious dip. Although I didn't receive a direct response from Sankovitch, that post immediately became a highly viewed one, making me reasonably sure she read it and possibly forwarded it to others. Good enough.
Next: A short note (short for me anyway) to Barbara Ehrenreich's blog right on the heels of finishing "Bright Sided" (2009) - terrific, if sobering book about positive thinking. Glad I gave myself permission to begin doing this. What have you resisted giving yourself permission to do?