I'm using the UBB Classic, version 6.7.2, with all of the email options enabled, but cannot find the "UBBFriend:Email this page to someone!" link that the User Manual claims is associated with each topic. Could you tell me where it is? Thanks.

You can see it on this very thread - look above your post.

The control for the feature is on the Primary Settings -> Email page.

For some reason, the link did not appear anywhere on my board. But when, in response to your message, I went to the control panel, unchecked "Enable UBBFriend Feature?" box, then checked it again and saved the changes, the link magically appeared on one forum. But it did not appear on the forum from which I wanted to send a message. Is there something else I need to do?

Private forums do not allow UBBFriend. In addition, if the page is cached, you might not see the link immediately update.