When Google bought DoubleClick in April, they triggered not just demands by competitors for the regulators to stop the deal, but a string of similar acquisitions. What followed this tipping point can be seen in the list on the right, which is from the WSJ (subscription required). Just one month after Google's acquisition, Yahoo, the WPP Group - and now Microsoft - spent tons of money paying premiums for other online ad companies. The online ad market is predicted to reach $20 billion this year - the same size as radio ads - and the shift from traditional media to new media will continue for the next few years. This will leave the printed media in particular with empty hands. In a market that was always slow-moving one can expect that most of them won't be able to react fast enough in shifting their own focus online, too.