Bing advertisers can now retarget their customers on Bing and Yahoo for both Search and Shopping campaigns. The process of setting up Bing Ads Remarketing is very much similar to Google AdWords with the incentive of using it in the Shopping campaigns too.
Bing uses UET Tracking Code to report user activity. This activity is then matched with the remarketing lists and users that performed matching actions are added to the remarketing lists. Bing Ads requires atleast 1000 users in the remarketing lists before campaign can be optimized.
Remarketing Now Available In Bing Ads!,