The Internet enables billions of people to communicate and exchange and/or access services, among many other activities. Accessing many services on the Internet involves logging in to the service—typically using login credentials such as a username and/or password. Generally, each user maintains his or her own account associated with each service they use. For example, a user might have an account with an email provider, another account with a payment service or bank, and still another account on a social network.
Initially, each user has to create their account by going through a registration process. The registration process may involve many different steps, and typically varies based on the type of account being created. However, this is not a perfect system—fake accounts may be created. A fake account is an account used for malicious, or otherwise unapproved, reasons. For example, some users may register multiple accounts when they are supposed to be limited to a single account. Users may register for multiple accounts for many different reasons—some reasons may even be legitimate. For example, a malicious user may register for multiple accounts so that he or she may harass another user, send spam messages, or perform other malicious activities. This is of particular relevance to accounts on social networks or other services where users may communicate with other users of the service—although the invention is not limited to social networks, and may be used with any service having accounts.
Identifying these fake accounts as fast as possible would increase the value and the quality of the service provided. Previously, solutions have involved review and/or approval of each account registration. However, that solution is impractical when popular services may receive thousands, tens of thousands, or more, registrations per day.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.