1. A non-transitory computer-readable medium storing computer-executable instructions that when executed by a computer cause the computer to: receive a query data point q for classification, wherein the query data point q represents attributes of a user that accessed a website over a network using a remote computing device; access and select an arbiter point to perform classification of the query data point q; access a first set of classified data points belonging to a first known classification, wherein the first set of classified data points is based upon first responses to a first type of content by users associated with the first known classification; for the first set of classified data points: for one or more data points in the first set, selecting a classified data point x c from the first set belonging to the first known classification to form a data point pair (q, x c ) with the query data point q; calculating a tripoint arbitration coefficient for the data point pair based, at least in part, on a first distance between the query data point q and the classified data point x c , a second distance between the query data point q and the arbiter point, and a third distance between the classified data point x c and the arbiter point; and determining a first class-aggregated similarity metric for the query data point q with respect to the first known classification of the first set based, at least in part, on the tripoint arbitration coefficients for data point pairs that include the query data point q and the classified data point x c in the first set, as calculated using the arbiter point; and repeating the selecting, the calculating, and the determining for the query data point q using one or more data points in a second set of classified data points belonging to a second known classification to determine a second class-aggregated similarity metric for the query data point q as being similar to the second known classification, wherein the second set of classified data points is based upon second responses to the first type of content by users associated with the second known classification; classifying the user based on at least the query data point q as belonging to the first known classification corresponding to the first responses or the second known classification corresponding to the second responses based on a comparison of the first class-aggregated similarity metric and the second class-aggregated similarity metric of the query data point q; selecting content from a set of content based on whether the user is classified as belonging to the first known classification corresponding to the first responses or the second known classification corresponding to the second responses, wherein the selected content is for rendering by the website; and transmitting the selected content over the network to the remote computing device to render through the website on a display of the remote computing device.