Yet classifieds are peculiarly vulnerable to the Internet's capacity to permit one-to-one communications across great distances.

Small class size promotes one-to-one communication and rapport between teacher and student, which best stimulates the desire to learn.

"This is not about one-to-one communication," Mr. Joseph explained.

"You narrow down email primarily to what it was designed for, which is one-to-one communications."

He says one-to-one communication is sometimes preferable to marketing studies.

It is mainly designed for group communication in discussion forums, called channels, but also allows one-to-one communication via private message.

Moreover, some say, there might not be much demand for one-to-one communications, given the ease of using the Web.

Some companies that did not use much direct mail realized that there were benefits to one-to-one communication.

They then share information about hypotheses (diffusion of information) through direct one-to-one communication.

"Paging" is the one-to-one communication between the mobile and the base station.