1. A machine-implemented method comprising: receiving a set of tracking data from a monitored activity, wherein the set of tracking data includes a plurality of name-value pairs; comparing the received set name-value pairs with one or more sets of context masks, wherein each of the sets of context masks include one or more name-filter pairs; selecting one of the sets of context masks in response to determining that the incoming name-value pairs match the mask name-filter pairs of the selected context mask; selecting one or more of the name-value pairs, the selected name-value pairs being based upon the selected context mask; storing the selected one or more name-value pairs in an aggregate data store; and disregarding the received set of tracking data in response to determining that the name-value pairs fail to match at least one of the name-filter pairs.