In the game collections page (where it breaks down the games by system) if you hit prioritize, then that game goes to the front of the list. You can bump the priority up multiple times.
If you haven't hit the priority button at all, then the games in your profile page are displayed by the latest edition.
so... the games on your profile page are sorted in the following order. Priority, then by add date, and the first 30 games are shown








