A number of people are exchanging e-mail messages everyday using mobile phones and PDAs. E-mail is useful not only for oneto-one communication but group communication through mailing lists. However, conventional mailing lists are not as widely used as they should be, because creating and maintaining a mailing list is not an easy task. We propose a simple and powerful mailing list service system called QuickML, with which people can easily create a mailing list and control the member account only by sending e-mail messages. QuickML allows people to enjoy group communication at any place, at any time, and by anyone. Categories and Subject Descriptors H.4.3 [Communications Applications]: Electronic mail; H.5.3 [Group and Organization Interfaces]: Asynchronous interaction General Terms Design, Human Factors Keywords Mailing list, groupware, ubiquitous computing, QuickML