Numbers on this site with certain units (e.g. "300 miles") have been specially processed such that a decent browser will let you click on them to toggle between metric and imperial units.
My email address as it appears on this site has a number in it that gets changed every day. My mail filters reject an address more than a few days old in order to foil spammers who find my address in these web pages. This substantially cuts down on spam without making it difficult for real people to contact me. My normal address is "seth@..." and will not expire any time soon.