P.S. The postscript is becoming an afterthought.

As people increasingly communicate in short bursts of words, via text messaging and emails, they are finding less use for "P.S." The Latin abbreviation refers to something "written after" the body of a letter. But it is also a cherished part of epistolary tradition that entered the spoken language, inspiring songs and movies.

One reason for the decline of "P.S." is that anything after a sign-off may get missed. Today, emails are landing in crowded in-boxes and never get read beyond the subject line or first few sentences. "I don't think people are reading email, they're scanning," says Janelle Estes, a specialist at Nielsen Norman Group, a Fremont, Calif.-based firm that studies how people interact with technology....