When entering a new topic I would like to ask for the email address of the writer. When I reply I would like to send the answer automatically to the writer of the topic
If topic's writer is registered and has email he receive notification about your response automatically.
I understand, but I don't want my website-visitors to have to register at userecho first.
We have one idea for you.
Try disable "Allow anonymous feedback" in the privacy settings for your forum. And after that try logiut and leave feedback. Click "Not registered yet" and you will see email field.
Registration required just email and name.
Now We work on the simplification of the registration form. I think it will be like email field from start, and additional fields (if need) after input email. I think it very close to your request.