The following clues employ the same "trick." Can you determine what it is and fill in the remaining blanks to form a  common name or phrase. 

1.  _ _ _ _   KOLE
2.  OLING  _ _ _ _
3.  BEO   _ _ _ _ _ _
4.  STO  _ _ _ _ _ _ _
5.  SHAO  _ _  CARO
6.  FOE  _ _ _ _ _ _ _
7.  HIO  _ _ _ _ _ _

 HINTS:
A: It has to do with the shape of one of the letters.
B: More clues:
     1. He has a list.
     2. Greatest Show on Earth
     3. Former land bridge
     4. Chamber music piece
     5. Sappy expression
     6. Company car, for one
     7. Economic slowdown consequence

Answers:

The letter O is in the shape of a ring, and stands for the letters RING:

1. KRIS KRINGLE
2. RINGLING BROS
3. BERING STRAIT
4. STRING QUARTET
5. SHARING IS CARING
6. FRINGE BENEFIT
7. HIRING FREEZE

Credit: Merl Reagle  (Idea & #1-2)
CIRCLE OF FRIENDS