ReferenceUSA is an Internet-based reference service that contains, in module format, detailed information on more than 12 million U.S. businesses; 102 million U.S. residents; 683,000 U.S. health care providers.

Information is compiled from the following public sources: more than 5,600 Yellow Page and Business White Page telephone directories; annual reports, 10-Ks and other SEC information; Continuing Medical Education (CME) directories; federal, state, provincial and municipal government data; Chamber of Commerce information; leading business magazines, trade publications, newsletters, major newspapers, industry and specialty directories; and postal service information, including both U.S. and Canadian National Change of Address updates.

ReferenceUSA's residential information is compiled from more than 3,900 White Page telephone directories. Each listing appears in the database exactly as it appears in the phone book. ReferenceUSA does not include unlisted phone numbers, Direct Marketing Association and Canadian Marketing Association suppression files, or state-regulated mail and telephone suppression files (U.S. data only). Information is available eight to 12 weeks after it appears in the phone book, and the file is processed through U.S. and Canadian National Change of Address records on a monthly basis.