My first instinct was to derecommend responding, but on second thought I guess it depends on what you'd say. If you have a really humorous story about how you came to sell your book as a series, one your publisher wouldn't mind you sharing, then maybe. But if the comment you want to make wouldn't be both *very* humorous and *very* substantive, then I would say no, and if you're in doubt as to the wittiness and value of your contribution, I would say no. And if you do, be careful -- it strikes me it would be so easy to come off as snooty or defensive or "explainy" when responding to something like that, at least in my experience.
Just MHO, of course.