An explanation
The following is from the administrator in answer to your question. It was given to a similar question on the forum in Oct., 2008.
Clues in the format: "The five people are A, B, C, D and E" can be extremely helpful when solving logic puzzles, as they allow you to eliminate quite a lot of squares from the solving grid.
Remember that every one of the five slots in that clue (A, B, C, D and E) are five different people, so none of the five items listed will ever be paired with another item from that list. This means you can eliminate a large number of possible pairings from the grid, i.e.
 A does not equal B
 A does not equal C
 A does not equal D
 A does not equal E
 B does not equal C
 B does not equal D
 B does not equal E
 C does not equal D
 C does not equal E
 D does not equal E
Hope this helps! :)
 Stephen
