Thank you for this detailed reply. You've certainly convinced me to at least weigh the option more carefully. (And you're right, I never would have predicted that many confirmed emails off of that link, in part for the reasons you cite about prominence etc. And my low prediction was even though I knew that HN traffic numbers, just in terms of number of hits to the submitted page, could be potentially staggering. I thought your link would have very few takers despite the extra traffic to the page it's on.)

I think one thing that is missing is that there is not an obvious social norm of how many emails are absolutely okay. (e.g. if you bought something from me this year, is it okay to email you once a month? once every two months? twice a year? weekly?) wonder if you have any thoughts about this. (Sorry if I missed this in the post.)