After subscribing, your email address is retained in a file on the server until the website is updated (which happens regularly). After that, your email is retained in a local file, and backed up occasionally.
I send out an occasional newsletter to your email address. This happens only very infrequently, if I have new art to show.
You can always remove your email address by clicking on a link in the newsletter, or by visiting this page. Your email address will then be completely purged from my files. A copy of your email address may remain in a backup until I make a new backup, which happens frequently.