Summary: Here's everything you need to know before Wednesday's opening bell: Amazon bought smart doorbell maker and former Shark Tank contestant Ring. Weight Watchers shares rallied after-hours after beating Wall Street's earnings estimates. Same-store sales at Papa John's dived 3.9% in the fourth quarter. Square beat estimates but its stock still fell after yesterday's close. U.S. stock futures pointed higher. Watch TheStreet's investing interviews on Youtube
