Methods and systems for identifying visitors to real-world shopping venues as belonging to a group

Techniques disclosed herein identify visitors who visit a real-world shopping venue as belonging to a group. This involves tracking a physical action of a visitor present at the real-world shopping venue and identifying the visitor based on the tracked physical action and previously collected visitor information associated with the venue. The visitor is determined to be a member of a group based on the previously collected visitor information. Based on determining that the visitor is a member of the group, a notification is sent to another member of the group. The notification identifies that the visitor has placed at least one item in a sharing cart while the visitor is present at the real-world shopping venue. A system determines that visitors who routinely visit a real-world shopping venue belong to a group based on their activities while visiting the venue, and allows the visitors to provide feedback to each other.