I've been reading Gustav Schenk's book "The Romance of the Postage Stamp," which Julie kindly gave me. Written in 1959 it is, as the jacket promises, an absorbing history of this paper currency. These two passages came to mind. The first, in light of the events in Egypt:

That a person's communication - in other words, his active contribution to the world, his real and genuine freedom - could travel from London to the Scottish Highlands for only a penny was remarkable enough...; but behind the economy in money and time lay a still greater triumph - the confirmation of the sovereignty of the citizen. It was an unlimited penny freedom for the middle classes, a total victory for liberalism.

And the second, in honor of Valentine's day (within a discussion of the adhesive agents used at the time):

A Frenchman, however, a great epicure, held an entirely different opinion. A love-letter of his from the 1850s has been preserved.: 'The stamp, O love of my life, which you placed on your letter, I swallowed with delight because I knew that you, my angel, had licked it!"

Which reminds me of the story told by author and illustrator Maurice Sendak who received fan mail from a young admirer, replied and, weeks later, got a note back from the boy's mother thanking Sendak for the postcard which her son, so overcome with excitement, ate.