GREENE: While the threat has been out there for years, and now the day is about to arrive when letters will no longer arrive in your mailbox on weekends. The U.S. Post Office is about to announce cutbacks in Saturday service beginning this summer. The postal service expects to save $2 billion a year. Now, packages will still come on Saturdays. They're a growing business for the postal service, thanks to online shopping. Email, though, is a big reason for the Post Office's financial woes. Transcript provided by NPR, Copyright NPR.