How does advertising with Yahoo differ from Google?

I saw the above chart today from eMarketer and it surprised me a bit.  I hear so much about Google adwords that I expected their income from ads to be higher.

How does advertising with Yahoo differ from Google?  I found an interesting comparison from mybesttradingwebhosting.com that showed some comparisons between advertising with each of the sites:

Yahoo! Advertising

Yahoo! Advertising gives its advertisers custom solutions to choose from that allow for brand building and response drives.

The more popular solution is the company’s sponsored search solution. This program allows advertisers to control the overall marketing cost by setting a daily budget. Advertisers can also set the amount they wish to pay each time an advertisement is clicked and payments are only made for those ads clicked upon. Additionally, advertisers can stop specific ads and completely close out their advertising account at any time, no questions asked.

The Yahoo sponsored search solution has a reach of over 2.3 billion potential clients and customers. To even further narrow an advertising customer base, advertisers can utilize the company’s geo-targeting feature – allowing for very specifically targeted marketing. Created ads can also be rotated to see which message garners the most traffic. In-depth reporting is part of the program and offers the ability for advertisers to see results in real-time.

Google AdWords

Google AdWords allows advertisers the ability to choose keywords related to their business or service and create ads based on these selections.

Just like its counterpart, Google AdWords allows for setting a specified budget and advertisers only pay for actual clicks on their ads rather than any set daily or monthly amount. Advertisements can be placed on hold or removed entirely when it is found that some ads are garnering more traffic and customers than other ads.

As one of the most used search engines, Google AdWords can offer an extremely large base of potential customers. For local businesses wishing to target a more specialized and specific audience, Google AdWords offers the ability to narrow advertising regions to a particular region, state or even city. Customers can be targeted to within 20 miles of a business’ front door. Additionally, ads can be set to show a business’ location when searchers are seeking data within Google.com and Google Maps.