The present invention has been made in consideration of thin devices efficiently communicating ideas and transactions into data networks by using other devices with full functional user interface in the networks. According to one aspect of the present invention, the thin device exclusively controls the authentication of a rendezvous that is associated with a user account in a server. The thin device running a micro-browser provisions the rendezvous with a set of credential information in an authenticated and secure communication session so that the provisioning process is truly proprietary. To access the user account, the other devices equipped with well-known browsers must submit the correct credential information to the rendezvous for verification in the server. Once admitted, the other devices can update managed information in the user account, individually and respectively, thereby the thin device is able to conduct desired transactions based on the managed information in the user account without the need to key in pertinent information of the transactions.