How do you get someones's e-mail address?

If I reply to this email that a yahoo user sent me will they get my email address?

• I answered a question and the user that asked the question emailed me. I clicked on the email and it gave me the email and under it, it said, "To continue the conversation click this link" and it gave me a link and it said You received this email because you are opted in to receive communications from others through Yahoo! Answers Messaging blah blah blah...please do not reply to this message blah blah blah...and something about editing communication preferences. I wanna respond but not if they get the email address because it isn't my email address that Im using its my sisters (but it is my yahoo answers account she doesn't use it) When I got the email i didn't get his address. If I respond will he get the address that I'm using?

• Answer:

  If you use the email service here on answers, then no, Yahoo keeps our address private. You don't get a copy in your sent folder. You have to click the link provided in the email Yahoo sent you. Not reply in your regular mail. It's safe.