{HEAD ~ Determination} of user affinity groups may be made by {TAIL ~ comparison} of user profiles 
made by
{ HEAD ~ Determination } of user affinity groups may be made by { TAIL ~ comparison } of user profiles
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH