In certain categories users on Adverts now have the option when creating their ads to copy them over to DoneDeal.
To manage the shared ad and access messages, etc on DoneDeal you should log in to your DoneDeal account.
If you have an existing DoneDeal account registered to the same email address the shared ad will be placed on that account.
If you didn't already have an account under the email address registered to your Adverts account a new account will have been created for you.
The first time you try to log in to your new DoneDeal account you should use the Forgotten Password function in order to set a password.