This article explains that Yahoo! does not provide transaction services, and lists internet resources for users who believe they may be the victims of fraud.   
 

Yahoo! does not act as a third party for any transactions including automobile sales. As such, anyone claiming Yahoo! is an intermediary for transactions is incorrect, and as such, is doing so fraudulently.

Yahoo! does not offer any of the following services:

• The ability to pay bills directly through Yahoo! (Our Billpay service was discontinued in July of 2007)
• Provide wire transfer or escrow services
• Act as an intermediary for online or other transactions
• Serve as a transaction guarantee service

Note: If you have had any correspondence with someone claiming that Yahoo! does, in fact, provide some of the services listed above, please see the following resources where such fraud can be reported.

If you think you may be a victim of fraud and are within the United States contact the Internet Crime Complaint Center, United States Postal Inspection Services, or Federal Trade Commission.

If you are not in the United States, then please contact your local fraud authorities.

It may also be appropriate to contact your local law enforcement officials (through a non-emergency number.) More information on fraud can be found at National Internet Fraud Watch Information Center.

Here is the list of services that Yahoo! offers:

• The ability to keep track of stock portfolio through My Portfolios
• The ability to track a transactional portfolio or $Cashline through My Portfolios
• The ability to watch a specific stock or security on a real-time basis
• Access to lots of financial information through our many financial partners
• Through our Yahoo! Real-Time Quotes subscription service, you can have access to MarketTracker and other Yahoo! Premium services. (This is only available int he United States)
• Provide Personal Finance tools such as calculators, expert opinion, and a financial glossary
• Provide information and quotes for foreign markets