Prepare a server comprising an information provider, a login processor, a user storage unit, a mail sender, and the like, on the internet. The information provider provides information while improving contents of incentive (prize or the like) as increase of the number of terminals which have logged in via the internet. The login processor refers to the user storage unit. If the terminal being login is a new corner, the login processor notifies the information provider of it. The information provider counts the number of the terminals which are logging in based on the notification. The mail sender sends mails for promoting usage of new information (promotional mail) to users who have already utilized the similar service. The mail sender also sends the promotional mails to persons who have introduced by the members of the service.