Traditional book promotion -- the type of book publicity campaign that involves mailing out books/media kits and following up to pitch reviews and interviews -- just got a bit more expensive. The price of mailing a United States Postal Service flat-rate envelope (the type of mailer that's supposed to be used for documents but that accommodates a trade book, too, most of the time, as long as you don't have to apply tape to keep the mailer closed) just went up to $4.95.
The postal rate increases (which apply to Priority and Express packages) might make some authors and publishers (and book publicist) think twice before committing to massive, blind, untargeted mailings. There are much beter ways to conduct book promotion campaigns. There always have been (online book promotion campaigns have always been far more efficient than traditional book promotion campaigns). Now book promotion specialists and others have more incentive than ever to make the switch.