Customer groups and sales promotions

A method performed by one or more computers of a transaction processing system, the method comprising:

• receiving data at the one or more computers of the transaction processing system from a mobile point-of-sale (POS) device associated with a merchant, the data indicating, for each of multiple purchase transactions:
• an identification of a customer with whom the purchase transaction was conducted;
• a time of the purchase transaction;
• a transaction total amount;
• a product purchased in the transaction;
• a purchase price of the product;
• and
• a category of the product;
• analyzing the data to determine purchasing behaviors of multiple customers, the purchasing behaviors of a customer comprising two or more of the following:
• times of purchase transactions conducted by the merchant with the customer;
• categories of products purchased by the customer from the merchant;
• prices of products purchased by the customer from the merchant;
• total transaction amounts for purchase transactions conducted by the merchant with the customer;
• total transaction amounts for purchase transactions conducted by the merchant with the customer during respective time periods;
• a number of purchase transactions conducted by the merchant with the particular customer;
• a frequency of purchase transactions conducted by the merchant with the particular customer;
• a time of a most recent purchase transaction conducted with the particular customer;
• or
• a number of reward points held by the particular customer;
• analyzing the purchasing behaviors to identify a group of customers having similar purchasing behaviors with respect to the merchant;
• determining a sales promotion that is likely to be effective for the group of customers based on the similar purchasing behaviors of the group of customers;
• and
• sending a notification to each customer of the group of customers, the notification describing the sales promotion.