In early May, we’ll be retiring the position preference bidding feature in AdWords. If you’re using position preference, we recommend that you disable the feature in your campaigns prior to that date to ensure a smooth transition for your bids.
More specifically, you can expect to see the following changes in your account: As of today, April 5th, position preference can no longer be enabled for campaigns through either the AdWords web interface or the API. Campaigns already using position preference will still have it enabled, but if you turn position preference off in one of your campaigns, you won't be able to turn it back on. Starting in early May, we'll begin disabling position preference for any campaigns still using it. After you disable position preference (either manually or when the feature is retired starting in early May), the manual maximum CPC bids for those campaigns will be the bids position preference used most recently. Position preference tries to raise or lower your bids to target the positions you specify. So using the most recent position preference bid as your manual maximum CPC should minimize disruption to your traffic.
This is really bad news for the way I handle adwords - the top positions convert the best for me, while the lower ones do not. Hence with a limited budget I use position preference to make sure that when my ads appear, they do so in the best converting positions.
This is going to increase my cost per conversion and overall adspend considerably - great for Google, not so good for me!