A data storage system or service is provided for the data that is generated by the personalization system. The data storage system can be configured to support storing, retrieving or querying, and updating of data such as user information, personalized content such as personalized business information and collection information, statistics information related to users, collections, businesses, and the like. The data model design of the data storage system may be configured to optimize performance associated with specific features of the personalized system such as following and/or sharing of collections. Additionally, the data storage system may be configured to detect and provide user notifications of trigger events.