1. A system for dynamically defining a web feed, the system comprising: a memory unit adapted to store web feed data and to generate a web feed of selected web content; an input processor in operative communication with the memory unit configured to receive a user input defining one or more remote websites and to retrieve remote web content from the one or more remote websites; a user interface configured to display a set of identified elements from the remote web content in a display area of a primary website; a selection processor in operative communication with the user interface configured to receive a user selection identifying one or more selected elements of the remote web content; an equivalency engine in operative communication with the selection processor and configured to calculate equivalency classes comprising subsets of the identified elements determined to be structurally similar to the selected elements; a web feed processor configured to generate a web feed for display to the user on the primary website, wherein the web feed includes at least the selected elements and one or more of the subsets of the identified elements determined to be structurally similar to the selected elements; wherein the selection processor is further configured to update the display area of the primary website to visually emphasize the identified elements from the remote web content that are determined to be structurally similar to the selected elements; wherein the selection processor is further configured to receive a second user selection selecting one or more other identified elements that were not visually emphasized, or de-selecting one or more visually emphasized elements; and wherein the equivalency engine is further configured to update the calculated equivalency classes based on the user selection of the identified elements or de-selection of the visually emphasized elements.