A minimum bid cap is the lowest bid you wish to make for a particular keyword.

It is often useful to define this amount in very competitive industries, or areas with a large amount of minimum bid advertisers so your listing does not get lost among the minimum bidders.

Even setting a minimum bid of $0.15 at Overture, for many keywords, can increase your total internet visibility by a significant amount.

In most cases, your bids will be above the minimum allowed bids for the two major pay per click search engines (Overture and Google AdWords). Both of these pay per click accounts have features that can lower your bid above the minimum you specify in a pay per click manager (if you specify a bid amount higher than their minimum bid), so setting such a limit does not generally affect bids with little or no competition as your bid will be automatically lowered.

In highly competitive industries where there are dozens of advertisers, and you do not want your listing to be lost among the minimum bidders, setting a minimum bid of $0.15 will generally raise your internet visibility by a decent amount.