A platen for a molding machine includes an intermediate support structure between two planar walls having ribs arranged at a non-normal angle \u03b2 to a first wall. One embodiment provides a pressure-waveform sensor having a housing, a support element, and a piezoelectric element having a first end secured between the support element and the housing, and a second end in a cantilevered orientation. When the calculated profit is positive, the BT company arranges for the visitor to be tagged with a tag readable by the selected media property through which the BT company expects to profit.