A very wide variety of physical, demographic, biological and man-made phenomena have been observed to exhibit powerlaw behavior, including the population of cities and villages, sizes of lakes, etc. The Internet is no exception to this. The connectivity of routers, the popularity of web sites, and the degrees of World Wide Web pages are only a few examples of measurements governed by powerlaw. The study of powerlaw networks has strong implications on the design and function of the Internet.Nevertheless, it is still uncertain how to explicitly generate such topologies at a very large scale. In this paper, we investigate the generation of P2P overlays following a powerlaw degree distribution. We revisit and identify weaknesses of existing strategies. We propose a new methodology for generating powerlaw topologies with predictable characteristics, in a completely decentralized, emerging way. We provide analytical support of our methodology and we validate it by large-scale (simulated) experiments.