How is Yahoo! different/similar to Google marketing?

Billing

Yahoo! Sponsored Search allows advertisers to decide on the maximum amount they want to pay for every click that their ad gets. It sets a minimum account balance and sends you a bill when that amount has been reached—which may mean multiple charges each month.

Google Adwords has no minimum spending requirement. It accumulates advertising clicks and sends you a bill every month.

Keywords feature

Google Adwords allows its clients to choose the keywords that relate to their business, and offers cost estimates as well as keyword traffic to allow its clients to make more-informed decisions on selecting keywords to help maximize their budget.

Yahoo! Sponsored Search also comes with an interesting, but much less powerful keyword-help feature, where various keywords (relevant to your business) will be displayed for advertisers to select from.

ADs Matching
Google Adwords uses a technology called contextual targeting that automates the matching of ads to relevant web pages in the Google content network. Google Adwords also offers its advertisers greater control by allowing them to hand-pick particular sections of websites where they wish to see their ads appear.

Using Yahoo! Sponsored Search, the maximum cost-per-click and the quality of your ad determines where the ad will be displayed in the search results.

Reporting
Google Adwords advertisers can measure results using the placement performance report, through which an ad's performance can be reviewed site-by-site, to determine better-performing websites that should be targeted more aggressively.

Yahoo! Sponsored Search data are only updated daily.