United Airlines recently announced a change to its checked bag policy for customers purchasing non-refundable domestic economy tickets. According to the new policy, travelers purchasing non-refundable domestic economy tickets, who do not have status in Mileage Plus or Star Alliance, will be able to check one bag for free, and a second bag for a fee of $25 USD (one way). The previous rule had allowed for two checked bags free of charge.
The new policy applies to tickets purchased on or after February 4, 2008, for travel on or after May 5, 2008—for travel within the 50 United States, Puerto Rico, U.S. Virgin Islands, and Canada.
Travelers who have reached Premier status or higher in the Mileage Plus program, or those who have reached Silver status or above with a Star Alliance airline, are exempt from the policy change. Additional details can be found here.
Sources: United.com, Los Angeles Times