Although Yahoo! Groups safeguards your email address from mass harvesting, you should know that in most cases, your email address will become known to the group through normal interaction. Please read this page carefully to understand the details concerning the visibility of your email address on the service.

• If you post a message to the group via email, your email address will appear in the message. (This is standard email protocol and there's no way of getting around it.)
• Whenever a page containing your email address is displayed to other members or made "public" to non-members, we mask your address to prevent mass harvesting. For example, if your email address is "joe@xyfoobar.com," we display "joe@x..." However, in most cases, the owner and moderators of your group can see your email address (it won’t be masked for them as they often need to see member addresses to manage the group).
• Some groups allow you to hide your email address entirely from the group (including from the group owner and moderators). If you choose this option, your email address won’t be disclosed to the group at all, but you must post messages to the group from the Groups web site. (You’ll still be able to receive group messages via email). Please note that not all groups offer you this option, as it is a per-group setting controllable by the creator of the group.
• If you’re concerned about your email address being known to other members, we suggest you set up a special address for community services like Groups. You can easily do that by signing up for Yahoo! Mail.