It's becoming increasingly obvious that one of the major virtues of free software is that you can patch it to change its behaviour, but aside from operating system vendors, there's no central repository for patches for most software. This would be something that sites like Freshmeat and SourceForge.net could provide: a list of unofficial patches that users had contributed. Both users and developers could then easily see what was available, and OS vendors wouldn't have to duplicate each others' patches.