1. A method for identifying one or more current user activities, comprising: obtaining, by a computer, user-action information associated with a current user activity, wherein the current user activity is initially unspecified, and wherein the user-action information is gathered automatically without user intervention and comprises unsupervised data corresponding to the activity's primitive operations; identifying, from a plurality of classified user-action information subsets that each comprises supervised data, one or more classified user-action information subsets whose associated user-action information matches the received user-action information; calculating a weighted sum of the identified matches; calculating, based on the weighted sum, a probability that a current user activity corresponds to a respective classified user-action information subset; determining, based on the calculated probability, a classified user-action-information subset which corresponds to the received additional user-action information; identifying a classified user activity that corresponds to the determined user-action-information subset.