The SubscribeLink accesses the subscription screen where you can instruct the ZWiki whether or not to send you email. It is the word subscribe displayed at the top right corner of the page.

You can subscribe to the current page or to the whole wiki. Subscribers to a page are emailed comments with heading that are made to that page. Subscribers to the wiki receive comments as if they were subscribed to every page in the wiki. In addition, they are emailed notification of new pages and page deletions. See MailOut.