Credit Reporting Agencies aka Credit Bureaus: There are 3 major credit bureaus: Equifax, Experian, and Trans Union. They are private companies that compile your financial information for companies who wish to extend you credit.
Subscribers aka Data Furnisher: These are the companies reporting your account information to the credit bureaus. They report information like payment history, account balance, date of last activity, etc. Credit reporting is voluntary, so how often this info is reported, and which credit bureau this info is reported to varies by company. These variations are why your credit scores differ between credit bureaus.
Credit Reports: Are a tool to help companies decide whether to give/extend you credit. You have 3 credit reports, 1 of each credit bureau. There are many types of credit reports, and all have different formats, but they generally contain 5 sections of information: