When you release your finger a box pops up with a choice of lists to add the message to.

FORBES: Mailbox App Revolutionizes Gmail Productivity, Will Google (Or Apple) Buy It?

Published in 2005, it reached the top of several bestseller lists with its headline message that the world is now just one big integrated market.

ECONOMIST: Idea

Users can rate songs, create "recommended" lists and party mixes and message them to other subscribers.

FORBES: On The Cover/Top Stories

James Capretta, a former budget official under Mr. Bush, who is now a fellow at the Brookings Institution, says presidents put together these lists in part to deliver a message.

NPR: Battle Looms over Cuts in Federal Programs

One side benefit, at least for me, is that since the app encourages you to make a judgement about each message, you quickly realize that many of those mailing lists that you have subscribed to (many through incentive or manipulation) are extraneous.

FORBES: Mailbox App Revolutionizes Gmail Productivity, Will Google (Or Apple) Buy It?

In America and in Britain, on both the hardback and paperback lists, non-fiction books with a life-affirming or self-improving message are holding their own against those with a downbeat one.

ECONOMIST: What the world is reading