Amazon probed by US Mail

Amazon is under investigation by the US Postal Service for "compliance with Postal Service rules," according to a one-sentence statement in the company's annual 10-K filing with the US Securities and Exchange Commission.

"In January 2009, we learned that the United States Postal Service, including the Postal Service Office of Inspector General, is investigating our compliance with Postal Service rules, and we are cooperating," the filing reads.

As might be guessed, speculation abounds as to the nature and scope of the investigation.

Is Amazon, for example, following Postal Service rules and regs to the letter when it uses the USPS's lower-cost Media Mail service?

Bulk-mailing expert Ron Wiener, as quoted on TechFlash, has one intriguing theory: "The USPS is absolutely desperate for revenue so one of the very first things they'll do is go after major accounts and see if there's any revenue leakage."

Whether Amazon is not playing by the rules, only time - and the USPS investigation into leaky revenue - will tell.

Amazon did not immediately respond to our request for comment. ®