The problem of abuse of privileges at cloud-hosted service sites is addressed at the sign-up stage by identifying suspicious or abusive users and preventing them from signing up in the first place. This approach may utilize a relatively small initial data set based on the recognition that while abusers' profiles are mutable and difficult to characterize stably—abusers will deliberately shift their usage patterns to evade detection—a site's legitimate users tend to have similar and stable characteristics; that is, such characteristics are “cohesive” across cloud-hosted service (e.g., social media) sites and their users. The information gleaned from analysis of this small data set can be applied to a much larger, unsorted data set to obtain profiling criteria based on a large population for statistical reliability.