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 {HEAD ~ a very strong indicator} of {TAIL ~ the item preferences} of users 
of
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 { HEAD ~ a very strong indicator } of { TAIL ~ the item preferences } of 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 HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH