For the average class-level player this is not a particularly crucial area but it's not something which should be ignored either. Fritz6 comes with a database of over 300,000 games and this database is a wonderful reference tool for researching and working on your openings. As an example, you might play the Caro-Kann Advance variation as White and like to see games in which this variation was played. The first thing you'll see is screen after screen of game headers. There are a number of ways to tackle this.
Capital letters mean that there are a lot of variations or commentary in the game.
Even excluding your viewing to commented games will often still provide you with an overwhelming amount of material, which you still need to pare down. My personal preference is to play through the games in chronological order. This is why Paul Morphy's or Adolf Anderssen's games are so much easier to understand than Garry Kasparov's. In this particular case, you'll notice that only three Caro-Kann Advance games in the database were played before 1960. If you decide to work on annotated B12 games chronologically, your first game will be Hort-Seirawan, Bad Kissingen 1981.