I think it'd depend on the content of your email to be honest. If it was a whinging one, I'd say the chance of a reply were slim to none. If it was a nice "ooooo you're ace, annd I love your site Mr Ed" I imagine you'll get a reply- eventually.
Subsequently, i've never ever recieved a reply as mine have always been the former ;-)
Thank you. It was neither a criticism nor a compliment. I wouldn't waste my time on either. It was just a question, a relevant one, which I wanted an answer to.