The U.S. Postal Service forecasts the coming Holiday season will be its busiest ever. The service said it is expecting to handle 365 million packages, a 20% increase in the number it handled last year. On top of that, it says it will deliver nearly 18 billion cards and letters between Thanksgiving and New Year's Eve. The jump comes as the Postal Service faces serious financial problems. Rival shippers are expecting smaller increases in shipments. FedEx is expecting a 13% increase, while UPS is forecasting a nearly 9% increase. The shift to online shopping is one of the reasons package shipments are expected to go up so much.