Google announced on Google+ that Google may now use your remarketing lists as a quality factor for your AdWords ads, which may impact your AdWords Ad bids and CPCs.
Starting today, our automated bidding strategies that use conversion data, specifically Conversion Optimizer, Target CPA and Target ROAS will use advertiser-built remarketing lists as real-time signals for search ads, to fine-tune bids and increase conversion volume. This means that our automated bidding technology will now increase or decrease your bids based on the performance of your remarketing lists, in addition to other real-time signals, like location, browser or time of day.
So now part of the bidding algorithm are completely non-search related factors outside of landing pages and so forth. Remarketing lists are built into it.
Here is the example Google provided:
Let’s say you’re trying to drive newsletter subscriptions for your business via search ads, so you set up a conversion event to track newsletter signups. Since you know it takes a couple of website visits before customers subscribe to your newsletter, you might create a remarketing list of people who have visited your website but didn’t sign up. Starting today, Conversion Optimizer will automatically adjust bids for visitors in your remarketing list based on projected lifts in conversion rates. This helps you fine-tune the way you reach customers who visited your website, but haven’t signed up for your newsletter yet.
Forum discussion at Google+.