Of the 32,741 post offices in America, the Postal Service is reviewing about 3,200, or nearly 10 percent. The Postal Regulatory Commission, an independent agency, posted 700 of them on a 12-page list at its Web site, www.prc.gov -- but the site was almost impossible to reach, apparently overwhelmed by people trying to find out if their local branch was in danger.

The Postal Service is in trouble, both because of the economy and changing times. People are paying bills online instead of putting a check in an envelope; they are sending E-mail instead of letters. The Postal Service says it may lose $7 billion this year.

It has already been doing what it can to protect itself. The price of a first-class stamp has gone up two cents this year, to 44 cents. The agency has 150,000 fewer employees than it did in 2000.

Last week, the Government Accountability Office (GAO) put the Postal Service on its "High-Risk List of federal areas in need of transformation." It said it expects mail volume to drop by 28 billion pieces in 2009, to a total of 175 billion envelopes, boxes and the like -- this at a time when the number of addresses in America has been growing by 1.2 million per year.

"Mail volume has bounced back after past recessions, but USPS's forecast suggests that may not be the case this time as more and more postal customers embrace electronic options," the GAO said in a press statement.

Postmaster General John Potter has already asked Congress for permission to cut mail deliveries from six days a week to five. The post office does not get taxpayer funds to operate. The Postal Service says no branches will close before Sept. 30.

The postal service stressed that not all the offices on the list may close -- and others may be added.

"The Postal Service urgently needs to work with Congress and other key stakeholders to develop and implement a restructuring plan to help put it on a more sustainable financial path," said Gene Dodaro, the head of the GAO.

"By adding the U.S. Postal Service's financial condition to the High-Risk List, we hope to bring attention to the agency's financial viability and its ability to provide sustainable, affordable, high-quality mail service."