Fresh Fish, Flowers, Cartons of Water … What's Next for the Postal Service?

With traditional letter mail in slow decline, the Postal Service is eager to bolster its finances by developing new lines of business that leverage its massive delivery network and capabilities.

But getting such ventures off the ground is not always easy or simple. USPS and 1-800-Flowers announced a deal in late 2012 but only now are getting ready for a limited test in New York.

Another growing Amazon-USPS partnership is Amazon Fresh, which delivers groceries to doorsteps in parts of the New York, Los Angeles, Seattle, and San Francisco areas...