Disclosed are various embodiments for tracking, in at least one computing device, a presentation of a plurality of items for a user, each item being associated with at least one respective category of a plurality of categories, and determining a user histogram that is customized for a user. A visual symbol may be generated based at least upon the user histogram for each category, each visual symbol comprising a visual characteristic for associating the visual symbol to the category and a graphical dimension of the visual symbol, wherein the graphical dimension correlates with the respective degree of interest associated with the category. Each visual symbol may be appended to one another to form a graphic identifier and a user interface encoded for rendering, where the user interface comprises the graphic identifier.