For example, in the context of an online store or marketplace, the matching service may primarily or exclusively analyze user purchase data, which tends to be a very strong indicator of {HEAD ~ the item preferences} of {TAIL ~ users} 
For example , in the context of an online store or marketplace , the matching service may primarily or exclusively analyze user purchase data , which tends to be a very strong indicator of { HEAD ~ the item preferences } of { TAIL ~ users }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL