$100 million is apparently the marketing budget 'magic number' to prove you're serious relaunching your search engine... and has been for 10 years. From October 1999:
"Internet investment firm CMGI plans to spend more than $100 million on a 12-month advertising campaign that trumpets major changes aimed at transforming its AltaVista Web directory into a top-tier portal player, sources say."
Alas, the ad blitz didn't do much to revive AltaVista, and it won't be the size of the marketing campaign spend that determines what happens for Bing.
