Depending on permission settings, users can contact each other via email or via the messenger ID if it is made public on the profile page.
Answers does not facilitate contact by email unless you explicitly allow it. When you set up your answers profile, you tell us what contact information you'd like other users to see. You choose whether or not you'd like users to be able to contact you via Answers email, Yahoo! Instant Messenger, or Yahoo! 360.
When setting up your Answers profile, you choose a setting for the following options:
Contact permissions are always controlled by you in your Answers profile. To make changes to your profile and contact permission settings, go to My Profile and select the Edit My Info link.
Email: When you enable email communications, Answers never shows your email address to the recipient (neither on the email nor on your profile page.) The only way to reply to Answers email is by clicking the reply link within the email and sending the message through Yahoo! Answers. If a person doesn't have their email communications enabled, you won't be able to send them an email message.
Messenger: Your instant message ID will be seen publicly on your profile page if you enable IM communications.
Please remember that chatting and posting your email address in your questions or answers are violations of Answers community guidelines, so please communicate to each other through the IM and email features instead.