An information database in communication with an information application comprises a plurality of marketplaces and {HEAD ~ a plurality} of listings respectively classified within the plurality of {TAIL ~ marketplaces} 
An information database in communication with an information application comprises a plurality of marketplaces and { HEAD ~ a plurality } of listings respectively classified within the plurality of { TAIL ~ marketplaces }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL