The server then receives, from a client, a request for an advertisement to display to the first user, selects one of {HEAD ~ the other users} having a friend rank satisfying a predetermined threshold, and transmits, to the client, an advertisement portraying {TAIL ~ the selected additional user} 
The server then receives , from a client , a request for an advertisement to display to the first user , selects one of { HEAD ~ the other users } having a friend rank satisfying a predetermined threshold , and transmits , to the client , an advertisement portraying { TAIL ~ the selected additional user }
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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL