Crackers mostly post the cracks to IRC sites, cs.rin.ru, and private torrent sites. Repackers are the main way releases make it to the mainstream torrent sites.

Repacking isn’t that complicated anymore, it’s more about reputation. There was a time when games were big and internet speed was slow so saving every MB of size was important. Repackers would reencode video files and find other ways of dramatically reducing the file size. Nowadays they don’t do a lot of that, but repackers are still important for casual pirates who just want to easily play pirated games and not worry about malware.

Cracks are usually released separately from the uncracked game files. Repackers take those cracks and package them with the correct version of the game, compress the files and add an installer. Then they upload them to the more mainstream public trackers.

Repacks have several benefits. They tend to be easier to setup and usually more reliable. They download faster and use less data because they are compressed. They are also sometimes packaged with extras like soundtracks, mods, etc.

Fitgirl repacks are known to be more compressed, so the files are a little smaller but take a fair amount longer to install.