YOU are browsing for lampshades on a department store's website.
You grow bored, and surf across to the website of your favourite
daily newspaper. Mysteriously, the lampshades follow you: an
advertisement for the same brand appears next to the article you
are reading. Welcome to the world of real-time bidding, a
cleverer and nosier way of selling advertising that is beginning
to shake up the online media business.  A decade ago online
display advertisements, or “banners” as they were often known,
were booming. Companies paid huge sums to appear on news
websites. But, as the number of ads increased, people stopped
noticing them. Now, for every 1,000 display ads that pop up,
less than two are clicked on. Prices have slumped. Some media
firms, notably News Corporation, have concluded that online ads
will never bring in enough money to support a newspaper.
Meanwhile search advertising, which reaches people when they
seem to be interested in something, has grown from 1% of
American online ad spending in 2000 to al