Tradelines, or Trade Lines, are simply your credit accounts, which are reported to the credit reporting agencies. Each tradeline contains detailed information about the account.
A primary tradeline is an account that shows on your credit report as your account, versus being an authorized user's account.As it stands, the practice of adding a primary tradelines to your credit report and paying to do so is perfectly legal.
An updated tradeline is an account on your credit report that has been updated. If someone with a good credit score adds you as an authorized user to one or more of their seasoned tradelines-like a credit card-you can reap the benefits of their positive credit history.