The present invention relates to techniques for controlling transfers of information in computer networks. One technique involves transmitting from a server computer to a client computer a document containing a channel object corresponding to a communication service, and storing an access ticket that indicates that a user of the client computer permits the information source computer to communicate with the user over a specified channel. Another technique involves transmitting smart digital offers based on information such as coupons and purchasing histories stored at the computer receiving the offer. Another technique involves transmitting from a server computer to a client computer a request for a user's personal profile information, and activating a client avatar that compares the request for personal profile information with a security profile of the user limiting access to personal profile information. Another technique involves transmitting from a server computer to a client computer a document containing an embedded link, activating the embedded link at the client computer and recording activation of the embedded link in a metering log.