Great article this week in BusinessWeek (may 8 2006) on the Yahoo & MSN Attack Google. Here are some take aways:

1. The 1st quarter of 2004 showed Yahoo at .25 billion and Google at about .35 billion
2. The 1st quarter of 2005 showed Yahoo at about .4 billion and Google at about .8 billion
3. The 1st quarter of 2006 showed Yahoo at .5 billion and Google at 1.5 billion

The numbers above are for ad search growth. Google is now at 49% of the search-oriented ad business in the U.S. Last year they were at 33%.

1. Google has about 400,000 ad clients
2. Yahoo has about 200,000 ad clients
3. MSN is now starting from basically scratch

The numbers above reflect the number of ad clients.

According to the article, although MSN and Yahoo have made tweaks to thier system, they are following the market leader, and are not really introducing anything new. Most analysts expect Google to continue to widen thier lead, Yahoo and MSN are merely slowing the pace!