Thanks for your question. Although the concept of “maximum bid” (the most you’re willing to pay for any single click) is still in place in the new Yahoo! advertising system, in the account interface we now use the terms “default bid” and “custom bid.”

A default bid is a bid set at the ad group level that is applied to all keywords in that ad group, unless a custom keyword bid is specified. For example, if you set a default bid of $.50, you won’t pay more than $.50 per click on all keywords in that ad group that do not have custom bids.

A custom bid is a bid that can be set at the keyword level to override a default bid. In the example above, if you set your default bid for an ad group to $.50, you might decide to set a custom bid for your most profitable keyword in that ad group at $.75, in which case the most you would pay per click for that keyword is $.75. Please note that custom bids can only be set for Sponsored Search keywords, not for Content Match.

More information on these types of bids can be found on this page in our Help Center: [help.yahoo.com...]

Hope this helps!

YahooPete