Back in August, it was announced that Bing Rewards would soon be replaced by the Microsoft Rewards program for those in the United States. The program's concept remains the same, but nomenclature, status, and ability to redeem points were all being modified.
Those changes appear to have taken effect today as noticed by @prjkthack who tipped us on the modification. The Bing Rewards page is now updated to reflect the new Microsoft Rewards status along with new features and redesign.
Some of the changes include points for using Microsoft's Edge browser, purchasing items in both the Windows Store and Microsoft Store. Other changes are more superficial e.g. instead of credits they are points. Bing Rewards had three levels (Member, Silver, and Gold), but Microsoft Rewards has Tier 1 and Tier 2 levels. If users earn 500 Microsoft Points a month, they will be a Tier 2 member and will be able to get a 10% discount on rewards from Microsoft brands. All current Bing Rewards members who signed up before August 15 will be upgraded to Tier 2 which will last until October 31.
Points can be exchanged for rewards such as gift cards at GameStop, Amazon, Starbucks, Hulu, and Microsoft brands.
You can head to the new site found at this link: account.microsoft.com/rewards.
You can read the full changes in the official Microsoft FAQ on the subject. As usual, Microsoft Rewards is U.S. only for the time being.