algorithmic modeling for Rhino
Data Matching is an extremely important aspect of Explicit History. The McNeel wiki pages contain a fair amount of information on the subject, but you can download this example file and see for yourself.
Essentially Data Matching algorithms kick in when inputs don't match up. If you connect a line component (two inputs, starting and ending points) to two lists of point coordinates that have a different number of points, it is not clear which points are supposed to be connected. You can pick among three different matching algorithms to find the one that suits you best.
Data Matching algorithms can be set on a per-component basis through the menu of the component.