1. A computer-implemented method comprising: presenting, on a web page, a text entry field for a text string to be entered by a user; receiving the text string, the text string including a delimited label list; parsing the delimited label list to determine a number of, and labels for, categorized user-selectable interface elements to display; presenting a graphical interface that includes a motion video presentation and the number of categorized user-selectable interface elements, each user-selectable interface element having a separate label from the delimited label list; receiving, through the graphical interface, at a first moment during the presentation, a first selection of a first interface element of the categorized interface elements; in response to receiving the first selection, storing first data that maps a first category, corresponding to the first interface element, to a first time point at which the motion video presentation was being presented at the first moment; and generating, based at least in part on the first data, a first tracking graphical element that indicates at least a first quantity of times that the first interface element has been selected during a first time interval that includes the first time point.
12. The computer-implemented method of claim 1 further comprising: assigning a color to each user-selectable interface element from the user who entered the text string.