List of related reports

Hi to all.
As everybody noted, at the end of our report we can read a list of related reports that have some waypoint in common with the waypoints of our one.
I have some question now:
1) What criterion is used to list that links? Is it chronological (it doesn't seem to me)? What other?
2) I see different colours for the links list. What does the colours mean?
3) Is the colour related to the colour that I can see on the "Calendar" of the user reports?
4) Are these colours connected and/or have they some relation?
Thank in advance
Giulio