The US is the birth place to one of the most advanced capabilities in conducting OSINT for usernames. The leading community backed capability currently available is UserSearch. It claims to offer the most robust Search Engine for Usernames, with supporting capabilities in emails and phone numbers. It's noted to provide reverse username searches for over 400 social networks and online communities, which is double that of any other Reverse Username capability online, including charged services. It claims to be free and community focused.