In this paper we present the first distributed measurement campaign conducted by the P2P framework Seattle. Seattle is a distributed PlanetLab like network testbed that easily enables everyone to participate. The contributions of the paper are the following: First, we conduct a thorough analysis of the prevalent conditions in the Seattle network and compare them to reference measurements obtained in a controlled test environment. We use the results to evaluate the usability of the testbed for distributed measurement campaigns and characterize the key parameters relevant to measurements. Second, we present our implementation of a coordinated, tournament-based all-pairs-ping program, which is used to obtain several latency matrices between Seattle test nodes. Additionally, we use the obtained results to present a simple case study that investigates the relation between geographic distance and latency of Internet paths, which is a key element for the geographic location of Internet hosts.