On Yahoo Personals, how can I tell if someone I write to is a subscriber or not?

Answer 1

They cannot respond in any way to your message if they are not a subscriber.The only way they can correspond with you is if you put your email address in the first note you send to them. If they wrote you a letter first and is not a subscriber, you may write them back but they could not send a reply to your message.
Hope that helps.