Development and projections in the field of PDAs and wireless communication architectures let us consider new applications which exploit short range and direct exchanges. In a close future we may imagine mobile users equipped with wireless PDAs dynamically and spontaneously exchanging rich information in an ad hoc manner. In such a context, a connection between two PDAs may be broken at any time because of the short communication range and the unconstrained mobility of the users. Thus, such spontaneous data exchanges become a real challenge. To perform spontaneous and relevant transmissions compatible with these volatile connections, we propose a method that progressively downloads information according to its importance. Then, we show an implementation of such a mechanism in a Web context by extending the actual browsers capabilities.