Optimized CPM allows an advertiser to prioritize their marketing goals, and then automatically delivers ads against those goals in the most effective way possible. This allows advertisers to maximize the value they get from their budgets.
Goals can be specified an absolute value, i.e. how much the fulfillment of a particular goal is worth to an advertiser. These values are not bids. For Optimized CPM, these values should be the value an advertiser places on each of those connections.
The system will automatically bid on behalf of the advertiser, while remaining constrained by the campaign budget they define and the values they specify. The dynamic bids allow the system to capture the highest-value impressions for your goals, and you should expect the total ROI on the campaign to exceed that of either a CPC or a traditional CPM campaign.