Here’s a breakdown  of Advertising in 2006, starting with the most first
1. Microsoft – more than 20 percent of their annual revenue or $11.5 billion
2. Coca-Cola – more than $2.5 billion
3. Yahoo – more than 20 percent of their annual revenue or $1.3 billion
4. eBay – 14 percent to 15 percent of its revenue – which was $871 million, much of that to advertise on Google
5. Google – In the millions rather than billions of dollars – with $188 million
6. Starbucks – $95 million

Source = reportonbusiness.com