The list at vespercalloway.com collects one thing: the email address you type in. It is stored on Amazon Web Services in the United States and used to send you the bonus scene and, occasionally, a note when a new book is out.
Nothing is sent until you click the confirmation link. Every email has an unsubscribe link; clicking it removes you at once. Addresses are never sold, shared or added to any other list. If you want your address deleted entirely, email hello at vespercalloway dot com and it will be.
The site sets no cookies and runs no tracking scripts. Like most sites, its server keeps a basic log of each page request: the page, the time, the site you came from, your browser type and your IP address. That log is private, is deleted after 30 days, and is used only to count visits. The counts keep no IP addresses, and nothing goes to any outside analytics company. Links to bookstores are plain links.