This article about Internet Advertising from the TimesOnline.co.uk is definitely worth reading.  Here’s an excerpt:

Advertising on internet soars as world follows British lead

The internet will overtake radio by next year and become the world’s fourth-largest advertising medium, a year earlier than forecast.

Global spending on internet advertising increased from $18.7 billion in 2005 to $24.9 billion (£12.6 billion) last year, according to ZenithOptimedia, the media-buying agency.

The Middle East and Asia are driving a boom in global advertising spending. Zenith predicted a spike of 7.7 per cent in spending in Asia in the run-up to the 2008 Olympic Games in Beijing.