Recent years, trend of researches in ad-hoc networks are routing, multicasting and optimized flooding. Focusing on data flooding in ad-hoc networks, proposed scenarios of common researches are limited due to lack of scalability. If there are lots of communication originators, it is obvious that wireless resources are inapplicable. In this study, our typical scenario is that a mobile ad-hoc network is deployed in a city area and many shops, such as shopping malls and restaurants, disseminate their commercial advertisements to the network. This paper points out the lack of scalability issues considering existing IP flooding schemes and proposes a novel application flooding scheme supporting automatic data size adaptation. In this scheme, size of flooded data is dynamically sampled depending on network congestion level so that data can be delivered in a scalable manner to all nodes using MANET.