It is what rigamagician said, but I don't find it hard to create the DB, given that when you find a position you want into your repertoire you just add it, no need to copy part of the game and paste it in a new database.
It is essentially a fast way to create a Garrybase
In Chessbase, you can set up a database with your repertoire, and then use it to search an archive of new games for games involving these lines. There are links earlier in this thread to how Garry Kasparov organizes his repertoire. I mostly use Chessbase's opening keys and the reference pane, but some people do put quite a lot of effort into building a repertoire database.