Windows only: If you've got an older USB drive that can't quite fit all the great launchers from the PortableApps.com site, AppCompactor rides to your rescue with serious compression tools—in some cases, anyways. The open-source (and, of course, portable) tool offers a range of compression methods, ranging in compatability and effectiveness, that knock down the executables, ZIP files, and other elements that get to work once you point it at your portable app folder. In the case of portable CCleaner, it took more than 30% off the size; with IM client Pidgin's portable, however, it reduced by just 5 KB. Still, for those looking to fit just a bit more onto their thumb drive, AppCompactor is worth a try. AppCompactor is a free download for Windows systems only.